Printable-Microencapsulated Ascorbic Acid for Personalized Topical Delivery.

This study presents the successful development of printable-microencapsulated ascorbic acid (AA) for personalized topical delivery using laser printing technology. Rice flour with a 10% AA content was selected as an encapsulation material. Hydrophobic nanosilica was used to create negative electrostatic charges on the microencapsulated surfaces via a high-speed mixture. This process facilitated the microencapsulated AA fabrication using a commercial laser printer and produced a well-patterned design with some minor print defects, such as banding and scattering. The amount of encapsulated AA per area was 0.28 mg/cm2, and the RGB color code was 0,0,0. An emulsion carrier system comprising pentylene glycol (P5G) or diethylene glycol monoethyl ether (DEGEE), Tween 20, oleic acid, and deionized (DI) water at a ratio of 20:30:30:20 was developed to enhance AA transmission into the skin. The Franz diffusion cell technique was used to investigate topical absorption on Strat-M membranes using P5G and DEGEE as enhancers. The steady-state fluxes were 8.40 (±0.64) and 10.04 (±0.58) µg/h/cm2 for P5G and DEGEE, respectively. Cytotoxicity tests conducted on fibroblast cells revealed low cytotoxicity for the encapsulation products and carriers.

L-Ascorbic acid and phosphatidylcholine complex vesicles: formation and elucidation of their biological activities, and their molecular interactions.

The aim is to prepare, characterise, and evaluate the biological activities and key molecular interactions of L-ascorbic acid and phosphatidylcholine (PC-AA) complex vesicles. PC-AA complexes were prepared and characterised using DLS, TEM, FTIR, UV-Vis, in-vitro release, bioactivities, and cytotoxicity. The key interactions of the AA with the PC were studied with MD simulations. PC-AA complex provides improved stability towards the degradation of AA in aqueous solutions while also slowing its release profile. The PC-AA complexes with an optimal molar ratio of PC: AA = 2.5:1 was shown to have a hydrodynamic diameter of 368.67 ± 4.65 nm and an EE of 68.16 ± 0.23%. At low concentration, the PC-AA complexes have no toxicity towards human dermal fibroblast cells over 48 h. Importantly, MD suggests that AA only forms the PC-AA complex when in its neutral form which is the desired active form. PC-AA complex could be a potential active to use in medicinal and cosmeceutical applications.

Coumarin-Caged Compounds of 1-Naphthaleneacetic Acid as Light-Responsive Controlled-Release Plant Root Stimulators.

Six coumarin-caged compounds of 1-naphthaleneacetic acid (NAA) comprising different substituents on the coumarin moiety were synthesized and evaluated for their photophysical and chemical properties as light-responsive controlled-release plant root stimulators. The 1H NMR and HPLC techniques were used to verify the release of NAA from the caged compounds. After irradiation at 365 nm, the caged compounds exhibited the fastest release rate at t1/2 of 6.7 days and the slowest release rate at t1/2 of 73.7 days. Caged compounds at high concentrations (10-5 and 10-6 M) significantly stimulate secondary root germination while free NAA at the same level is toxic and leads to inhibition of secondary root germination. The cytotoxicity of the caged compounds against fibroblasts and vero cells were evaluated, and the results suggested that, at 10-5-10-6 M, caged compounds exhibited no significant cytotoxicity to the cells. Thus, the caged compounds of NAA in this study could be of great benefit as efficient agrochemicals.

Abalone Collagen Extracts Potentiate Stem Cell Properties of Human Epidermal Keratinocytes.

Stem cell activities in human tissues are critical for tissue integrity and function. Maintaining keratinocyte stem cells (KSCs) stemness helps sustain healthy skin by supporting keratinocyte renewal, involving the formation of epidermal barriers. In this study, abalone collagen (AC) extracts with molecular weights of 3 kDa (AC 1) and 300 kDa (AC 2) were compared to the epidermal growth factor (EGF) for their effects on cell proliferation, cell migration (wound healing), spheroid formation, and the expression level of stem cell markers on human keratinocytes (HaCaT cells). Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell proliferation was quantified by ATP and DNA content analysis and Sulforhodamine B (SRB) assays. Cell migration assay was determined using the scratch wound healing test. Spheroid formation was evaluated and the expression level of stem cell markers was investigated by western blot analysis. The results showed that AC 1 at the concentration of 100 µg/mL could stimulate HaCaT cell proliferation, migration, spheroid formation, and the expression level of stem cell markers (keratin 19, ß-catenin, ALDH1A1) compared to the control. In conclusion, a smaller molecular weight of abalone collagen extract exhibits a better effect on keratinocytes proliferation, migration, and stemness, which could be a potential active ingredient in cosmeceutical products.

Micro- and Ultrastructural Characterization of Age-Related Changes at the Anterior Cruciate Ligament-to-Bone Insertion.

There remains a lack of understanding of the structural changes that occur across the complex, multitissue anterior cruciate ligament (ACL)-to-bone insertion as a function of aging. The objective of this study is to provide a multiscale comparison of matrix properties across the skeletally immature and mature ACL-to-bone insertion. Using complementary imaging methods, micro- and ultrastructural analysis of the insertion revealed that collagen fiber orientation at the interface changes with age, though the degree of collagen organization is maintained over time. These changes are accompanied by a decrease in collagen fibril density and are likely driven by physiological loading. Mineral crystal structure and crystallinity are conserved over time, despite regional differences in crystallinity between the interface and bone. This suggests that mineral chemistry is established early in development and underscores its important functional role. Collectively, these findings provide new insights into interface development and set critical design benchmarks for integrative soft tissue repair.