Converting Short-Acting Insulin into Thermo-Stable Longer-Acting Insulin Using Multi-Layer Detachable Microneedles.

The detachable dissolving microneedles (DDMNs) feature an array of needles capable of being separated from the base sheet during administration. Here they were fabricated to address delivery efficiency and storage stability of insulin. The constructed insulin-DDMN is multi-layered, with 1) a hard tip cover layer; 2) a layer of regular short-acting insulin (RI) mixed with hyaluronic acid (HA) and sorbitol (Sor) which occupies the taper tip region of the needles; 3) a barrier layer situated above the RI layer; and 4) a fast-dissolving layer connecting the barrier layer to the base sheet. RI entrapped in DDMNs exhibited enhanced thermal stability; it could be stored at 40 °C for 35 days without losing significant biological activity. Differential scanning calorimetric analysis revealed that the HA-Sor matrix could improve the denaturation temperature of the RI from lower than room temperature to 186 °C. Tests in ex vivo porcine skin demonstrated RI delivery efficiency of 91±1.59 %. Experiments with diabetic rats revealed sustained release of RI, i.e., when compared to subcutaneous injection with the same RI dose, RI-DDMNs produced slower absorption of insulin into blood circulation, delayed onset of hypoglycemic effect, longer serum insulin half-life, and longer hypoglycemic duration.

Dissolvable microneedles in the skin: Determination the impact of barrier disruption and dry skin on dissolution.

Dissolvable microneedles (DMNs), fabricated from biocompatible materials that dissolve in both water and skin have gained popularity in dermatology. However, limited research exists on their application in compromised skin conditions. This study compares the hyaluronic acid-based DMNs penetration, formation of microchannels, dissolution, and diffusion kinetics in intact, barrier-disrupted (tape stripped), and dry (acetone-treated) porcine ear skin ex vivo. After DMNs application, comprehensive investigations including dermoscopy, stereomicroscope, skin hydration, transepidermal water loss (TEWL), optical coherence tomography (OCT), reflectance confocal laser scanning microscopy (RCLSM), confocal Raman micro-spectroscopy (CRM), two-photon tomography combined with fluorescence lifetime imaging (TPT-FLIM), histology, and scanning electron microscopy (SEM) were conducted. The 400 µm long DMNs successfully penetrated the skin to depths of ≈200 µm for dry skin and ≈200-290 µm for barrier-disrupted skin. Although DMNs fully inserted into all skin conditions, their dissolution rates were high in barrier-disrupted and low in dry skin, as observed through stereomicroscopy and TPT-FLIM. The dissolved polymer exhibited a more significant expansion in barrier-disrupted skin compared to intact skin, with the smallest increase observed in dry skin. Elevated TEWL and reduced skin hydration levels were evident in barrier-disrupted and dry skins compared to intact skin. OCT and RCLSM revealed noticeable skin indentation and pronounced microchannel areas, particularly in barrier-disrupted and dry skin. Additional confirmation of DMN effects on the skin and substance dissolution was obtained through histology, SEM, and CRM techniques. This study highlights the impact of skin condition on DMN effectiveness, emphasizing the importance of considering dissolvability and dissolution rates of needle materials, primarily composed of hyaluronic acid, for optimizing DMN-based drug delivery.

Detachable-dissolvable-microneedle as a potent subunit vaccine delivery device that requires no cold-chain.

Although vaccine administration by microneedles has been demonstrated, delivery reliability issues have prevented their implementation. Through an ex vivo porcine skin experiment, we show visual evidence indicating that detachable dissolvable microneedles (DDMN) can deposit cargo into the dermis with insignificant loss of cargo to the stratum corneum. Using ovalbumin (OVA), a model antigen vaccine, as a cargo, the ex vivo experiments yielded a delivery efficiency of 86.08 ± 4.16 %. At room temperature, OVA could be stabilized for up to 35 days in DDMN made from hyaluronic acid and trehalose. The DDMN matrix could improve the denaturation temperature of the OVA from around 70-120 °C to over 150 °C, as demonstrated by differential scanning calorimetric analysis. In vivo delivery of OVA antigen into the mice's skin via DDMN elicited 10 times higher specific antibody responses compared to conventional intramuscular injection. We envision DDMN as an effective, precise dosing, intradermal vaccine delivery system that may require no cold-chain, offers a dose-sparing effect, and can be administered easily.

Efficacy and Safety of Detachable Microneedle Patch Containing Triamcinolone Acetonide in the Treatment of Inflammatory Acne.

Background: Detachable microneedles (DMNs) are dissolvable microneedles that detach from the base during administration. The use of DMNs-containing steroids for acne has never been investigated. Methods: Thirty-five patients with facial inflammatory acne were evaluated for acne treatment efficacy and safety of DMNs and DMNs containing triamcinolone acetonide (TA) via a 28-day randomized, double-blind, controlled trial. Four inflammatory acne lesions were selected from each participant and randomly treated with a single application of 700 µm DMNs containing 262.02 ± 15.62 µg TA (700DMNTA), 1000 µm DMNs containing 160.00 ± 34.92 µg TA (1000DMNTA), 700 µm DMN without TA (700DMN), and a control. Efficacy was measured by assessing physical grading, diameter, volume, erythema index, and melanin index. Safety was evaluated by assessing reports of adverse effects from patients and physicians. Results: All three treatment groups achieved resolution of inflammatory acne significantly faster than the control group, with median times for resolution of 4.6, 5.25, 6.7, and 8.1 days in the 1000DMNTA, 700DMNTA, 700DMN, and control, respectively. When compared to the control group, the diameters and post-acne erythema of inflammatory acne were significantly reduced in the treatment groups. The 1000DMNTA decreased acne size and erythema more than other treatments. DMNTA also tended to decrease acne size and erythema more than DMN with no TA, but there was no statistically significant difference. All participants preferred DMN over conventional intralesional steroid injection due to less pain and self-application. No adverse effect was observed. Conclusion: DMNTA is a safe, effective alternative treatment for inflammatory acne and significantly reduces post-acne erythema.

Delivery and diffusion of retinal in dermis and epidermis through the combination of prodrug nanoparticles and detachable dissolvable microneedles.

To minimize chemical degradation of retinal, we graft this aldehyde on chitosan chains to make them self-assemble into pro-retinal nanoparticles (PRNs), which we then load into detachable dissolvable microneedles (DDMNs) made of 1:1 (by weight) hyaluronic acid/maltose. The presence of PRNs in the hyaluronic acid-maltose needle matrix also helps improve the microneedles' mechanical strength. Ex vivo administration of PRN-loaded DDMNs on fresh porcine ear skin shows, as observed by stereomicroscopic and confocal fluorescence microscopic analyses of the cross-sectioned tissue pieces, complete deposition followed by dissolution of the needles and diffusion of the PRNs in epidermis and dermis. Rats administered with a single dose of PRN-loaded DDMNs show significantly increased epidermal thickness as compared to rats administered with control DDMNs (no PRN). Both the PRN-loaded DDMNs and the control DDMNs produce no skin irritation in rats.

The Efficacy and Safety of Chitosan on Facial Skin Sebum.

INTRODUCTION: Seborrhea or oily skin has been one of the most common complaints affecting both men and women physically and psychologically. Chitosan is a biopolymer obtained from the alkaline deacetylation of chitin. Due to its positively charged nature, chitosan can effectively bind to lipids. Therefore, chitosan nanoparticle (CN) formulation may benefit in the reduction of skin sebum. OBJECTIVE: The aim of this study was to evaluate the efficacy and safety of CN formulation in the reduction of skin sebum. METHOD: The study was a randomized, double-blinded, placebo-controlled trial in 24 participants aged 18-40 years with clinical seborrhea. Participants were randomly assigned to apply the CN and gum (CN-G) or placebo (gum alone) twice daily for 4 weeks. Sebum level, corneometry, transepidermal water loss (TEWL), and clinical seborrhea grading were evaluated at baseline and week 2 and 4. RESULTS: In the T-zone, sebum levels in the CN-G group were significantly lower than the placebo group at week 4 (p = 0.043), while for the U-zone, sebum levels were not different between groups. There were no statistical differences in corneometry and TEWL at any visit. Although the clinical seborrhea grading in CN-G was lower, it was not significantly different from the placebo. A few cases reported mild and self-limiting scaling and acneiform eruption. CONCLUSION: The CN-G gel could significantly reduce sebum levels on seborrhea patients with acceptable safety profiles.

Detachable dissolvable microneedles: intra-epidermal and intradermal diffusion, effect on skin surface, and application in hyperpigmentation treatment.

Delivering bioactive compounds into skin tissue has long been a challenge. Using ex vivo porcine and rat skins, here we demonstrate that a detachable dissolvable microneedle (DDMN) array, a special dissolvable microneedle that allows needle detachment from the base within 2 min post administration, can effectively embed a model compound into epidermis and dermis. Diffusion of the compound from the needle embedding sites to the nearby skin tissue is demonstrated at various post administration periods. The relationship between the time that a conventional dissolvable microneedle array is left on skin without needle detachment from the base and the degree of skin surface abrasion at each microneedle penetration spot is also demonstrated on skin of human volunteers. Co-loading glutathione with vitamin C (vitC) can stabilize vitC in the DDMN. DDMN loaded with vitC and glutathione can help erasing post-acne-hyperpigmentation spots.

Polymerized Luteolin Nanoparticles: Synthesis, Structure Elucidation, and Anti-Inflammatory Activity.

Luteolin is an anti-inflammatory flavonoid commonly found in many edible plants. The compound is popularly consumed as a supplement regardless of its poor water solubility (27.8 µg/mL at 25 °C) and low bioavailability. Here, mild one-pot polymerization of luteolin into water-dispersible nanospheres, with an average dry size of 234.8 ± 101.6 nm, an aqueous size distribution of 379.1 ± 220.5 nm (PDI = 0.338), an average ζ-potential of -36.2 ± 0.2 mV, and an 89.3 ± 4.8% yield, is described. The nanospheres consist of polymerized luteolin (polyluteolin) with a weight-average molecular mass of around 410000 Da. The chemical structure of polyluteolin is identified through 1H-1H correlated spectroscopy (COSY), 1H-13C heteronuclear single-quantum coherence (HSQC), and 1H-13C heteronuclear multiple-bond correlation (HMBC) NMR spectroscopic analyses of the oligomers, and a polymerization mechanism is proposed. Unlike luteolin that showed both dose-dependent anti-inflammatory activity and cytotoxicity when tested in lipopolysaccharide-stimulated macrophages, the polyluteolin nanoparticles possess dose-dependent anti-inflammatory activity without causing cell death even at high concentrations.

Microneedle-Facilitated Intradermal Proretinal Nanoparticle Delivery.

Topical retinoid treatments stimulate biological activities in the skin. The main physical barrier, which limits the efficacy of transdermal drug delivery, is the stratum corneum. Proretinal nanoparticles (PRN) have already been proven to efficiently deliver retinal into the epidermis. In the present study, two transdermal drug delivery systems, microneedles (MN) and PRN, were combined to directly target the dermis. The microchannels induced by the MN, the PRN localization in the microchannels and the skin closure kinetics were investigated by non-invasive imaging techniques, such as dermoscopy, optical coherence tomography and multiphoton tomography. Additionally, the amount of retinal in the epidermis and dermis after application in three different forms (PRN-Loaded microneedles, PRN suspension or conventional retinal solution) was compared. All imaging techniques confirmed the formation of microchannels in the skin, which were partly still detectable after 24 h. Multiphoton tomography showed the release of PRN from the MN within the microchannels. The recovered retinal concentration in the dermis was significantly higher when applied via PRN-loaded microneedles. We hypothesized that this platform of PRN-loaded microneedles can provide a rapid and efficient administration of retinal in the dermis and could be of benefit in some skin conditions such as atrophic scar or photo-aged skin.

The anti-sebum property of chitosan particles.

BACKGROUND: Seborrhea is linked to several medical and mental conditions. Although it is common, effective agents and the standardized sebum level for seborrhea are not elucidated. AIMS: To determine the efficacy of chitosan particles (CP) formulation on controlling sebum secretion, its extended effects on skin redness and texture after combining with proretinal nanoparticles (CP-PRN), and a correlation of the clinical grading with sebum levels that affect mental health. PATIENTS/METHODS: A four-week clinical trial with forty subjects was conducted. Subjects applied either CP formulation or CP-PRN during nighttime. Objective measurements including sebum levels, transepidermal water loss (TEWL), skin corneometry, skin redness, and texture were analyzed. Subjects completed a self-assessment clinical grading of skin oiliness at every visit. RESULTS: Both CP and CP-PRN significantly decreased sebum levels (P ≤ .01) at week 4 compared to baseline. CP also resulted in significant decreases in TEWL (P ≤ .05) and skin corneometry (P ≤ .05) throughout the study. A significant improvement in skin redness was observed with CP-PRN (P ≤ .01). A moderate correlation between the clinical grading and sebum levels was detected (coefficient of 0.5, P ≤ .001), with a sebum level of 106 µg cm-2 indicating emotional discomfort. One subject experienced local irritation with the CP-PRN. Mild pruritic symptoms were reported in both groups. CONCLUSIONS: Chitosan particles exhibited an interesting anti-sebum effect. It could be combined with PRN to extend benefits without losing the sebum controlling effect. The clinical grading may be useful in practice due to a modest correlation with sebum levels.

Solid Composite Material for Delivering Viable Cells into Skin Tissues via Detachable Dissolvable Microneedles.

Delivering cells to desired locations in the body is needed for disease treatments, tissue repairs, and various scientific investigations such as animal models for drug development. Here, we report the solid composite material that when embedded with viable cells, can temporarily keep cells alive. Using the material, we also show the fabrication of detachable dissolvable microneedles (DMNs) that can instantly deliver viable cells into skin tissue. B16-F10-murine-melanoma (B16-F10) and human-embryonic-kidney-293T (HEK293T) cells embedded in the solid matrix of the hyaluronic/polyvinylpyrolidone/maltose (HA/PVP/maltose) mixture show 50.6 ± 12.0 and 71.0 ± 5.96% survivals, respectively, when kept at 4 °C for 24 h. Detachable DMNs made of the HA/PVP/maltose mixture and loaded with B16-F10-cells were constructed, and the obtained DMN patches could detach the cell-loaded needles into the skin within 1 min of patch application. In vivo intradermal tumorgrafting mice with the DMNs containing 800 cells of B16-F10 developed tumors 10 times bigger in volume than tumors induced by hypodermic needle injection of suspension containing 100,000 cells. We anticipate this work to be a starting point for viable cell encapsulation in the solid matrix and viable cell delivery via DMNs.

Topical Proretinal Nanoparticles: Biological Activities, Epidermal Proliferation and Differentiation, Follicular Penetration, and Skin Tolerability.

Proretinal nanoparticles, the retinilidene-chitosan nanoparticles, have been developed to overcome the physicochemical instability of retinal and to lessen the dose-dependent cutaneous irritation, through sustaining the release of retinoid. Compared to conventional retinal at the same concentration, proretinal nanoparticles had no cytotoxicity and could induce a spontaneously immortalized human keratinocyte line to express more cellular retinoic acid binding protein-2. Compared to rats topically applied with conventional retinal which showed clear skin irritation and inflammation, daily topical application of proretinal nanoparticles to rats for 28 consecutive days produced neither irritation nor inflammation but significantly increased epidermal proliferation, epidermal thickness, cellular retinoic acid binding protein- 2 expression, and up-regulation of various differentiation markers including keratin 5, keratin 10, keratin 14, cellular retinoic acid binding protein-2, and proliferating cell nuclear antigen. Through the use of confocal laser scanning microscopy, we observed the in vivo follicular penetration of proretinal nanoparticles with the depth of penetration independent of postapplication time. Proretinal nanoparticles provide better biological activities of retinoids on epidermis and could eliminate the side effect of retinoid dermatitis.

Water-dispersible unadulterated α-mangostin particles for biomedical applications.

α-Mangostin, the extract from pericarp of Garcinia mangostana L . or mangosteen fruit, has been applied in various biomedical products because of its minimal skin irritation, and prominent anti-inflammatory, antimicrobial and immune-modulating activities. Owing to its low water solubility, the particle formulations are necessary for the applications of α-mangostin in aqueous media. The particle formulations are usually prepared using surfactants and/or polymers, usually at a larger amount of these auxiliaries than the amount of α-mangostin itself. Here, we show the self-assembly of α-mangostin molecules into water-dispersible particles without a need of any polymers/surfactants. Investigations on chemical structure, crystallinity and thermal properties of the obtained α-mangostin particles, in comparison to the conventional α-mangostin crystalline solid, confirm no formation of the new compound during the particle formation and suggest changes in intermolecular interactions among α-mangostin molecules and significantly more hydroxyl functionality positioned at the particles' surface. The ability of the water suspension of the α-mangostin to inhibit the growth of Propionibacterium acnes, the acne-causing bacteria, is similar to that of the solution of the conventional α-mangostin in 5% dimethyl sulfoxide. Moreover, at 12.7 ppm in an aqueous environment of RAW 264.7 cell culture, α-mangostin suspension exhibits five times higher anti-inflammatory activity than the conventional α-mangostin solution, with the same acceptable cytotoxicity of less than 20% cell death.

Sustaining Antibiotic Release from a Poly(methyl methacrylate) Bone-Spacer.

One of the challenges in using a bone-spacer to cure infection is the fabrication of a material that can continuously release required antibiotics at effective concentrations for at least 4-6 weeks. Poly(methyl methacrylate) (PMMA) impregnated with antibiotics is one of the popularly used bone-spacer materials. Currently, improved sustained release of hydrophobic and hydrophilic antibiotics is needed for this material. Here, hydrophilic vancomycin (VAN) was encapsulated into calcium citrate (CC) particles and natural rice granules, and hydrophobic erythromycin (ERY) was encapsulated into ethyl cellulose and poly(lactic-co-glycolic acid) particles. The four antibiotic-loaded particles were each incorporated into the PMMA cement. The two unencapsulated drugs and all four drug-loaded particles distributed well in the obtained composites. PMMA composited with VAN-loaded CC showed prolonged VAN release at an effective concentration for more than 40 days, but the composite possessed lesser compressive strength than the PMMA with no drug. PMMA composited with unencapsulated ERY showed a better sustainment of drug release than those composited with encapsulated ERY. VAN elution from the VAN-CC-PMMA did not significantly affect the compressive strength of the material, whereas ERY elution from the ERY-PMMA composite significantly decreased the material's mechanical strength.

Natural Thermoresponsive Rice Granules as Biocompatible Drug Carriers.

Through thermal gravimetric, X-ray diffraction, infrared spectroscopy, and scanning electron microscopic analyses, here we reveal that the 4-5 µm diameter pentagonal shaped rice granules are surprisingly stable against α-amylase, trypsin, lipase, diluted acids, and diluted bases. Some papain-sensitive proteins play an important role in the granular shape stabilization. We employ the reversible thermoresponsive expansion/shrinking character in aqueous medium of this biopolymeric pentagonal granular assembly to encapsulate the antibiotic vancomycin into the granule at the drug loading content of 80% drug mass with only 20% rice granule mass. The obtained drug-loaded granules display no-burst but steady sustained release of the water-soluble vancomycin in an aqueous environment for more than 24 h.

Oxidized carbon nanoparticles as an effective protein antigen delivery system targeting the cell-mediated immune response.

Background: The demand for an effective vaccine delivery system that drives a suitable immune response is increasing. The oxidized carbon nanosphere (OCN), a negatively charged carbon nanoparticle, has the potential to fulfill this requirement because it can efficiently deliver macromolecules into cells and allows endosomal leakage. However, fundamental insights into how OCNs are taken up by antigen-presenting cells, and the intracellular behavior of delivered molecules is lacking. Furthermore, how immune responses are stimulated by OCN-mediated delivery has not been investigated. Purpose: In this study, the model protein antigen ovalbumin (OVA) was used to investigate the uptake mechanism and intracellular fate of OCN-mediated delivery of protein in macrophages. Moreover, the immune response triggered by OVA delivered by OCNs was characterized. Methods: Bone-marrow-derived macrophages (BMDMs) from mice were used to study antigen uptake and intracellular trafficking. Mice were immunized using OCN-OVA combined with known adjuvants, and the specific immune response was measured. Results: OCNs showed no cytotoxicity against BMDMs. OCN-mediated delivery of OVA into BMDMs was partially temperature independent process. Using specific inhibitors, it was revealed that intracellular delivery of OCN-OVA does not rely on phagocytosis or the clathrin- and lipid raft/caveolae-mediated pathways. Delivered OVA was found to colocalize with compartments containing MHC class I, but not with early endosomes, lysosomes, and autophagosomes. Immunization of OVA using OCNs in combination with the known adjuvant monophosphoryl lipid A specifically enhanced interferon gamma (IFNγ)- and granzyme B-producing cytotoxic T cells (CTLs). Conclusion: OCNs effectively delivered protein antigens into macrophages that localized with compartments containing MHC class I partially by the temperature independent, but not clathrin- and lipid raft/caveolae-mediated pathways. Increased CD8+ T-cell activity was induced by OCN-delivered antigens, suggesting antigen processing toward antigen presentation for CTLs. Taken together, OCNs are a potential protein antigen delivery system that stimulates the cell-mediated immune response.

Increasing the percutaneous absorption and follicular penetration of retinal by topical application of proretinal nanoparticles.

Topical retinoids are frequently applied for therapeutic and cosmeceutical reasons although their bioavailability is low due to their chemical and photochemical instability. Moreover, skin irritation is a common side effect. Therefore, proretinal nanoparticles (PRN) as a novel formulation of topical retinoids, which are based on chitosan grafted with retinal through reversible linkage, were developed and their skin penetration behavior was studied. As nanoparticles preferably penetrate into the hair follicles, the follicular penetration depths of PRN at different time points were investigated. Moreover, the release capacity of the nanoparticulate system was studied using fluorescein as a model drug. Additionally, the concentration of retinal in the stratum corneum and in the hair follicles was quantified after application in particulate and non-particulate form. The results showed that the nanocarriers reached the infundibular area of the hair follicles, irrespective of the incubation time. The nanoparticles were able to release their model drug within the hair follicle. The retinal concentration delivered to the stratum corneum and the hair follicles was significantly higher when retinal was applied in the particulate form. In conclusion, the presented proretinal nanoparticle system may help to overcome the main problems of topical retinoid therapy, which are skin irritation, chemical and photochemical instability and low bioavailability, thus improving the topical retinoid therapy.

Oxidized Carbon Nanosphere-Based Subunit Vaccine Delivery System Elicited Robust Th1 and Cytotoxic T Cell Responses.

Subunit vaccines are safer and more stable than live vaccines although they have the disadvantage of eliciting poor immune response. To develop a subunit vaccine, an effective delivery system targeting the key elements of the protective immune response is a prerequisite. In this study, oxidized carbon nanospheres (OCNs) were used as a subunit vaccine delivery system and tuberculosis (TB) was chosen as a model disease. TB is among the deadliest infectious diseases worldwide and an effective vaccine is urgently needed. The ability of OCNs to deliver recombinant Mycobacterium tuberculosis (Mtb) proteins, Ag85B and HspX, into bone marrow derived macrophages (BMDMs) and dendritic cells (BMDCs) was investigated. For immunization, OCNs were mixed with the two TB antigens as well as the adjuvant monophosphoryl lipid A (MPL). The protective efficacy was analyzed in vaccinated mice by aerosol Mtb challenge with a virulent strain of Mtb and the bacterial burdens were measured. The results showed that OCNs are highly effective in delivering Mtb proteins into the cytosol of BMDMs and BMDCs. Upon immunization, this vaccine formula induced robust Th1 immune response characterized by cytokine profiles from restimulated splenocytes and specific antibody titer. More importantly, enhanced cytotoxic CD8⁺ T cell activation was observed. However, it did not reduce the bacteria burden in the lung and spleen from the aerosol Mtb challenge. Taken together, OCNs are highly effective in delivering subunit protein vaccine and induce robust Th1 and CD8⁺ T cell response. This vaccine delivery system is suitable for application in settings where cell-mediated immune response is needed.

Enhancing Passive Transport of Micro/Nano Particles into Cells by Oxidized Carbon Black.

Uses of micro-/nano-sized particles to deliver biologically active entities into cells are common for medical therapeutics and prophylactics and also for cellular experiments. Enhancing cellular uptake and avoiding destruction by lysosomes are desirable for general particulate drug delivery systems. Here, we show that the relatively nontoxic, negatively charged oxidized carbon black particles (OCBs) can enhance cellular penetration of micro- and nano-particles. Experiments with retinal-grafted chitosan particles (PRPs) with hydrodynamic sizes of 1200 ± 51.5, 540 ± 29.0, and 430 ± 11.0 nm (three-sized model particles) indicate that only the sub-micron-sized particles can penetrate the first layer of multilayered liposomes. However, in the presence of OCBs, the micron-sized PRPs and the two submicron-sized PRPs can rapidly enter the interiors of all layers of the multilayered liposomes. Very low cellular uptakes of micro- and submicron-sized PRPs into keratinocytes cells are usually observed. However, in the presence of OCBs, faster and higher cellular uptakes of all of the three-sized PRPs are clearly noticed. Intracellular traffic monitoring of PRP uptake into HepG2 cells in the presence of OCBs revealed that the PRPs did not co-localize with endosomes, suggesting a nonendocytic uptake process. This demonstration of OCB's ability to enhance cellular uptake of micro- and submicron-particles should open up an easy strategy to effectively send various carriers into cells.

The combined magnetic field and iron oxide-PLGA composite particles: Effective protein antigen delivery and immune stimulation in dendritic cells.

Superparamagnetic iron oxide nanoparticles (SPIONs) have received much attention in drug and biomolecule delivery systems. Here, we report a delivery system using the combination of a magnetic field and the relatively biocompatible composite particles of poly(lactic-co-glycolic acid) and SPIONs (SPION-PLGA particles) for protein delivery to bone-marrow derived primary dendritic cells (BM-DCs). SPIONs with the diameter of ∼10 nm were synthesized via thermal decomposition of iron(III) oleate. The SPIONs and bovine serum albumin (BSA) were encapsulated in PLGA particles of two different diameters, 300 and 500 nm. The obtained SPIONs-PLGA nanocomposites exhibited superparamagnetic character, showed low cytotoxicity and were well taken up in macrophage and BM-DCs under an external magnetic field. In addition, the nanocomposites were tested for immune induction in BM-DCs. This combined SPION-PLGA carrier and an external magnetic field can significantly enhance BM-DC maturation by upregulating MHC II, CD80 and CD86 expression. Immune response induction by this strategy is verified through a significant upregulation of the IL-12 and IFN-γ production. Moreover, no activation of BM-DCs to secrete pro-inflammatory cytokine TNF-α was observed for all particles. We anticipate these findings to be a starting point for vaccine researches involving the combined magnetic field and SPION-PLGA composite particles.