Recent Technological and Intellectual Property Trends in Antibody-Drug Conjugate Research.

Antibody-drug conjugate (ADC) therapy, an advanced therapeutic technology comprising antibodies, chemical linkers, and cytotoxic payloads, addresses the limitations of traditional chemotherapy. This study explores key elements of ADC therapy, focusing on antibody development, linker design, and cytotoxic payload delivery. The global rise in cancer incidence has driven increased investment in anticancer agents, resulting in significant growth in the ADC therapy market. Over the past two decades, notable progress has been made, with approvals for 14 ADC treatments targeting various cancers by 2022. Diverse ADC therapies for hematologic malignancies and solid tumors have emerged, with numerous candidates currently undergoing clinical trials. Recent years have seen a noteworthy increase in ADC therapy clinical trials, marked by the initiation of numerous new therapies in 2022. Research and development, coupled with patent applications, have intensified, notably from major companies like Pfizer Inc. (New York, NY, USA), AbbVie Pharmaceuticals Inc. (USA), Regeneron Pharmaceuticals Inc. (Tarrytown, NY, USA), and Seagen Inc. (Bothell, WA, USA). While ADC therapy holds great promise in anticancer treatment, challenges persist, including premature payload release and immune-related side effects. Ongoing research and innovation are crucial for advancing ADC therapy. Future developments may include novel conjugation methods, stable linker designs, efficient payload delivery technologies, and integration with nanotechnology, driving the evolution of ADC therapy in anticancer treatment.

Dexamethasone-Loaded Radially Mesoporous Silica Nanoparticles for Sustained Anti-Inflammatory Effects in Rheumatoid Arthritis.

Radially mesoporous silica nanoparticles (RMSNs) with protonated amine functionality are proposed to be a dexamethasone (Dex) carrier that could achieve a sustained anti-inflammatory effect in rheumatoid arthritis (RA). High-capacity loading and a sustained release of target drugs were achieved by radially oriented mesopores and surface functionality. The maximum loading efficiency was confirmed to be about 76 wt%, which is about two times greater than that of representative mesopores silica, SBA-15. In addition, Dex-loaded RMSNs allow a sustained-release profile with about 92% of the loaded Dex for 100 h in vitro, resulting in 2.3-fold better delivery efficiency of Dex than that of the SBA-15 over the same period. In vivo evaluation of the inhibitory effects on inflammation in a RA disease rat model showed that, compared with the control groups, the group treated with Dex-loaded RMSNs sustained significant anti-inflammatory effects and recovery of cartilage over a period of 8 weeks. The in vivo effects were confirmed via micro-computed tomography, bone mineral density measurements, and modified Mankin scoring. The proposed Dex-loaded RMSNs prolonged the life of the in vivo concentrations of therapeutic agents and maximized their effect, which should encourage its application.

pH- and temperature-responsive radially porous silica nanoparticles with high-capacity drug loading for controlled drug delivery.

The design of smart and functional nanocarriers for drug delivery systems that use a variety of organic and inorganic materials has led to the development of nanomedicines with improved therapeutic efficiency and reduced side effects. In this study, a pH- and temperature-responsive, controlled-release system with a high capacity for drug loading was developed based on radially porous silica nanoparticles composed of functionalized ligands and polymer encapsulation. This drug delivery system uses radially oriented mesoporous silica nanoparticles as the drug carrier, and control of the surface chemistry of those nanocarriers allows high-capacity loading efficiency of target drugs and stimuli-responsive release kinetics governed by pH and temperature. The delivery of ibuprofen was chosen to test this system, and a maximum loading efficiency of ca. 270 wt% was established, which was 3 times greater than that in previous studies for silica nanoparticles such as SBA-15, MCA-41, and MCM-48. In addition, the pH- and temperature-responsive release of ibuprofen was achieved when the surface of the nanocarriers was treated by pH-responsive amine functionalization and a temperature-responsive surface coating of agarose gel. Finally, cytotoxicity testing using the fibroblast cells showed that the developed silica nanocarriers have no toxicity on the cells, which should allow these nanocarriers to be applied as a nanomedicine in drug delivery systems.

Enhancing the evanescent field in TiO2/Au hybrid thin films creates a highly sensitive room-temperature formaldehyde gas biosensor.

Discovery of the relationship between disease and the volatile organic compounds (VOCs) contained in respiratory gas in human bodies has led to the development of analytical methods and detection systems that can be used for diagnosis. Recent studies, however, have encountered problems using these diagnostic tools when operation temperatures are too high and the detection range of the gas concentration falls beyond the limits of diagnosis criteria. In this study, we propose a highly sensitive surface plasmon resonance (SPR) biosensor that is based on an enhanced evanescent wave technique and can be operated at room temperature (RT) for the detection of formaldehyde. The detection system relies on an improved Kretschmann configuration with an enhanced signal transducer algorithm and a novel microfluidic gas channel that can accomplish highly sensitive quantification using ligand-modified TiO2/Au hybrid thin film as a RT-operated sensing interface. The detection of formaldehyde was chosen to test this concept, because formaldehyde is a known breast cancer biomarker that exists in human exhalation. When the interface of our sensing system was exposed to formaldehyde, the interaction between the ligand and the analyte produced changes in the SPR profiles of the gold thin film. The linear range of the detection system was 0.2-1.8 ppm with limit of detection at 0.2 ppm. The diagnostic criteria suggest this method could be applied to biological monitoring and diagnostics.

Novel color filters for the correction of red-green color vision deficiency based on the localized surface plasmon resonance effect of Au nanoparticles.

Color filters are promising tools for the correction of color vision deficiency because a medical cure of this physiological deficiency is unattainable. After the introduction of organic-dye based color filters, however, no appreciable progress has been made. In this study, gold nanoparticle-based plasmonic color filter devices, that is, EyEye-lens and EyEye-film, were developed for the correction of color vision deficiency. The EyEye-lens was prepared by a simple immobilizing technique, and the EyEye-film was readily synthesized through a one-pot method. These color filter devices are based on tunable localized surface plasmon resonance in the visible and near-infrared spectral range. Plasmonic nanoparticles embedded in the color filter provide a specific spectral color range for the correction of color vision deficiency. Careful color vision tests using an Ishihara plate were performed on subjects with red-green color deficiency. Statistical analysis of the color vision tests revealed that the EyEye-lens and EyEye-film have similar or better performance in the correction of red-green color deficiency than a commercial ChromaGen lens. The newly developed color filter devices should be considered as alternative personalized color filter devices for practical applications.

Sensitive Detection of Formaldehyde Gas Using Modified Dandelion-Like SiO2/Au Film and Surface Plasmon Resonance System.

To address the demands for the sensitive and real-time detection of formaldehyde gas at ambient temperature, a surface plasmon resonance (SPR) sensing system based on modified dandelion-like SiO2 nanoparticles/Au thin film is developed. The sensing system relies on modified SiO2 nanoparticles having radially arranged mesopores on the Au thin film, providing well-distributed and specific binding sites for formaldehyde and amplifying the sensing SPR signal. The linear range for the quantification is 0.2∼1.5 ppm with a limit of detection at 0.2 ppm. The regulation level of formaldehyde exposure suggests that the developed sensing system could be suitable to the real-time environmental and workplace monitoring.

A combined top-down/bottom-up approach to structuring multi-sensing zones on a thin film and the application to SPR sensors.

The development of a thin film with well-defined metallic micro/nanostructures, diverse surface functionalities, and superior electronic/optical properties has been a great challenge to researchers seeking an efficient method for the detection of various analytes in chemical and biological sensing applications. Herein, we report a facile and effective approach to the fabrication of an ordered gold island pattern on a glass substrate with contrasted chemical functionalities, which can provide spatially separated sensing zones for multi-detection. In the proposed method, the combination between the micro/nano-imprint lithography and sequential self-assembly approaches exhibited synergistic effects that allowed well-defined structuring and easy surface functionalization in separated sensing zones. Via imprint lithography, the uniform gold islands/glass structure was successfully fabricated from a readily available gold-coated glass film. In addition, a sequential self-assembling strategy and specific chemical-substrate interactions, such as thiol-gold and silane-glass, enabled the surfaces of gold islands and exposed portions of the glass substrate with contrasting chemical functionalities-SH-functionalized gold islands and NH2-functionalized glass substrate. A proof-of-concept experiment for the multi-detection of heavy metal ions (Hg(2+) and Cu(2+)) in an aqueous media was also successfully conducted using the dual-functionalized gold islands/glass structure and surface plasmon resonance measurements. The SH groups on the gold islands and the NH2 groups on the glass substrate functioned as spatially separated and selective receptors for Hg(2+) and Cu(2+) ions, respectively. Therefore, both the detection and quantification of Hg(2+) and Cu(2+) ions could be achieved using a single sensing substrate.

Sensitive and selective analysis of a wide concentration range of IGFBP7 using a surface plasmon resonance biosensor.

A sensitive method for selectively detecting insulin-like growth factor-binding protein 7 (IGFBP7) over a wide range of concentrations based on the surface plasmon resonance (SPR) biosensing techniques is described. IGFBP7 has been shown to regulate cell proliferation, cell adhesion, cellular senescence, apoptosis, and angiogenesis in several different cancer cell lines. Since the concentration of IGFBP7 can vary widely in the body, determining the precise concentration of IGFBP7 over a wide range of concentrations is important, since it serves as an inducible biomarker for both disease diagnosis and subsequent therapy. The SPR sensing method is based on the selective interaction of IGFBP7 with specific anti-IGFBP7 proteins on a gold thin film, which was covalently bound to the Fc-binding domain of protein G on a mixed self-assembled monolayer composed of DSNHS (S2(CH2)11COO(CH2)2COO-(N-hydroxysuccinimide)) and mercaptoundecanol, and effect of this on changes in the SPR profiles. The limit of detection (LOD) of the SPR biosensor was determined to be 10 ng/ml, which is a reasonable LOD value for biomedical applications. The response is essentially linear in the concentration range of 10-300 ng/ml. The SPR biosensor also shows specificity for IGFBP7 compared to that for biologically relevant interleukin (IL) derivatives including IL4, IL23, IL29, and IFG1. These molecules are also present along with IGFBP7 in the cell culture medium and have the potential to interfere with the analysis. Finally, the level secretion of IGFBP7 from cancer cells detected by the SPR biosensor showed a good correlation with a commercial kit using an IGFBP7 enzyme-linked immunosorbent assay. The findings reported herein indicate that the SPR biosensor for IGFBP7 would be applicable in a wide variety of biomedical fields.

Effect of end group modification of DNA-functionalized gold nanoparticles on cellular uptake in HepG2 cells.

Understanding the dynamics of the cellular uptake of nanoparticles in human derived (cancer) cells is crucial to the rational design of functional nanoprobes that can be used for the targeting and delivery of drugs. This study reports on the cellular uptake of gold nanoparticles (GNPs) that were functionalized with different oligonucleotide derivatives using HepG2 cancer cells as a model system. DNA oligomers, in which the end group was modified (NH3, PO3, OH, CH3, and SH groups) were introduced onto the GNP surface. Then, quantitative and qualitative analyses using each DNA-GNP complex were carried out via dark-field scattering microscopy and ICP-MS measurements. Visualization of microscopic images of single cells indicated that the uptake of DNA-GNPs was highly dependent on the type of functionality of the end group in the DNA-GNP complex; the functionality of CH3, and SH resulted in less cellular uptake than that for modifications with NH3, PO3, OH for the same incubation time. This result was reinforced by ICP-MS quantitative analysis. These results were also strongly supported by the events of a DNA-GNP/protein corona; the different association and dissociation rates of proteins around the GNPs was dependent on the functionality of the end group in the DNA-GNP complex, providing further evidence for the conclusion that the components on the surface of nanoparticles directly affected cellular uptake. The findings reported herein provide a basis for the understanding of the fate of GNP-based delivery and provide important insights into the rational design of nanoprobes for the effective treatment of various diseases.

Real-time analysis and direct observations of different superoxide dismutase (SOD1) molecules bindings to aggregates in temporal evolution step.

The misfolding and intracellular aggregation of Cu-Zn superoxide dismutase (SOD1) is pathologically key feature of amyotrophic lateral sclerosis (ALS). Although details of the mechanisms continue to be unclear, there are key steps in the possible pathway to the development of ALS. This study focuses on interactions between different SOD1 molecules (A4V apo/holo, and WT apo/holo) and homogeneous aggregates in the temporal evolution step, and a determination of whether any of the SOD1 molecules are reactive to the aggregates with the extent of binding, as determined by surface plasmon resonance (SPR) measurements. Using a kinetic binding model, the association constant of A4V apo was found to be three times larger than that for the WT apo species. Differences in the extent of the interactions were also simultaneously measured and visualized by means of SPR imaging techniques. The SPR-based approach suggests direct correlation between SPR signal and the extent of molecular binding, which can identify the significant contributors to the formation of macroaggregates of SOD1 in the temporal evolution step.

Colorimetric tracking of protein structural evolution based on the distance-dependent light scattering of embedded gold nanoparticles.

In this communication, we describe a new, simplified colorimetric method for in situ tracking of structural evolution of Cu/Zn-superoxide dismutase (SOD1) aggregates, based on changes in plasmonic coupling between gold nanoparticles (GNPs) embedded along the structural backbone of the SOD1 aggregates.

Sensitive and molecular size-selective detection of proteins using a chip-based and heteroliganded gold nanoisland by localized surface plasmon resonance spectroscopy.

A highly sensitive and molecular size-selective method for the detection of proteins using heteroliganded gold nanoislands and localized surface plasmon resonance (LSPR) is described. Two different heteroligands with different chain lengths (3-mercaptopionicacid and decanethiol) were used in fabricating nanoholes for the size-dependent separation of a protein in comparison with its aggregate. Their ratios on gold nanoisland were optimized for the sensitive detection of superoxide dismutase (SOD1). This protein has been implicated in the pathology of amyotrophic lateral sclerosis (ALS). Upon exposure of the optimized gold nanoisland to a solution of SOD1 and aggregates thereof, changes in the LSPR spectra were observed which are attributed to the size-selective and covalent chemical binding of SOD1 to the nanoholes. With a lower detection limit of 1.0 ng/ml, the method can be used to selectively detect SOD1 in the presence of aggregates at the molecular level.

The sensitive, anion-selective detection of arsenate with poly(allylamine hydrochloride) by single particle plasmon-based spectroscopy.

The use of single gold nanoparticle plasmon-based spectroscopy for the sensitive, anion-selective detection of arsenate is described. The method is based on the selective formation of electrostatic complexes between arsenate and poly(allylamine hydrochloride) (PAH) and changes in the single particle plasmon in Rayleigh scattering profiles. PAH, when modified with gold nanoparticles, binds arsenate via its amine-functionalities. The scattering properties of the resulting selectively formed complexes are altered, leading to significant changes in the surface plasmon resonance wavelength. The limit of detection of the method was determined to be 10 nM, which is ca. 13 times more sensitive than U.S. EPA regulation levels. The response is essentially linear in the concentration range of 50-300 nM. The method also shows good selectivity for arsenate in the presence of other environmentally relevant anions, including H(2)PO(4)(-), SO(4)(2-), NO(3)(-), and Cl(-).

Selective aggregation of polyanion-coated gold nanorods induced by divalent metal ions in an aqueous solution.

A simple, accurate method for detecting metal ions in an aqueous solution using functionalized gold nanorods (AuNRs) is described. The method involves the complexing of divalent metal ions with poly(acrylic acid) (PAA) and, the localized surface plasmon resonance (LSPR) phenomena of AuNRs. Changes in the longitudinal surface plasmon bands (LSPBs) were monitored using aggregates of PAA-coated AuNRs with various divalent metal ions via UV-vis spectroscope. Functionalized AuNRs underwent robust aggregate formation by chelation with divalent metal ions (e.g., Cu2+, Zn2+, Cd2+, and Fe2+). Copper ions formed largest aggregates within 2 h, because complexation between Cu2+ and dicarboxylate has the highest deltaH and -deltaG values. This process represents an easy and useful method for detecting certain divalent metal ions, and the aggregates are also, in some cases, clearly visible to the naked eye.

Picomolar selective detection of mercuric ion (Hg(2+)) using a functionalized single plasmonic gold nanoparticle.

A highly sensitive method for the selective detection and quantification of mercuric ions (Hg(2+)) using single plasmonic gold nanoparticle (GNP)-based dark-field microspectroscopy (DFMS) is demonstrated. The method is based on the scattering property of a single GNP that is functionalized with thiolated molecules, which is altered when analytes bind to the functionalized GNP. The spectral resolution of the system is 0.26 nm and a linear response to Hg(2+) was found in the dynamic range of 100 pM-10 microM. The method permits Hg(2+) to be detected at the picomolar level, which is a remarkable reduction in the detection limit, considering the currently proscribed Environmental Protection Agency regulation level (10 nM, or 2 ppb) and the detection limits of other optical methods for detecting Hg(2+) (recently approx. 1-10 nM). In addition, Hg(2+) can be sensitively detected in the presence of Cd(2+), Pb(2+), Cu(2+), Zn(2+) and Ni(2+), which do not interfere with the analysis. Based on the findings reported herein, it is likely that single-nanoparticle-based metal ion sensing can be extended to the development of other chemo- and biosensors for the direct detection of specific targets in an intracellular environment as well as in environmental monitoring.

Highly selective detection of Cu2+ utilizing specific binding between Cu-demetallated superoxide dismutase 1 and the Cu2+ ion via surface plasmon resonance spectroscopy.

A highly specific interaction between a metal-deficient metalloenzyme and metal ion has been utilized in the selective detection of the metal ion by surface plasmon resonance spectroscopy (SPRS). The use of SPRS and Cu-demetallated superoxide dismutase (E,Zn-SOD1) as a sensing actuator allows one to selectively and in situ detect Cu2+ without any interference that other spectroscopic methods may have.

Sensitive and colorimetric detection of the structural evolution of superoxide dismutase with gold nanoparticles.

The detection and characterization of protein aggregates are critical in terms of advanced diagnostic applications and investigations of protein stability. A variety of analytical methods (e.g., circular dichroism, size exclusion chromatography, and fluorescence microscopy) have been used in this regard, but they are limited in the trace detection of the structural evolution of protein aggregation. Here we report the gold nanoparticle (AuNP)-based highly sensitive and colorimetric detection of the temporal evolution of superoxide dismutase (SOD1) aggregates implicated in the pathology of amyotrophic lateral sclerosis (ALS). For the temporal discrimination of SOD1 aggregation, AuNPs were conjugated with SOD1 monomers (SOD1-AuNPs). Upon exposure of the probes (SOD1-AuNPs) with SOD1 aggregates, significant changes in both surface plasmon resonance spectra and concomitant colors were observed which are attributed to the formation of probe aggregates of variable sizes onto the SOD1 aggregates.

Construction of pcAFM module to measure photoconductance with a nanoscale spatial resolution.

A photoconductive atomic force microscopy (pcAFM) module was designed and the performance was tested. This module consisted of three units: the conductive mirror-plate, the steering mirror and the laser source. The module with a laser irradiation unit was equipped to a conventional conducting probe atomic force microscopy (CP-AFM) instrument to measure photoconductance in a nanoscale resolution. As a proof-of-concept experiment, the photoconductance of aggregated fullerene on indium tin oxide (ITO) substrate was measured with this module. The electrical signals (currents) of aggregated fullerene under the conditions of laser on/off at about -10 V sample bias voltage were -100 to -160 nA and 0 to -20 nA, respectively. Results indicated that the pcAFM with this module allowed one to observe photoinduced changes of electrical properties in nanodevices with nanoscale spatial resolution.

Fast image scanning method in liquid-AFM without image distortion.

High speed imaging by atomic force microscopy (AFM) allows one to directly observe the dynamic behavior of a sample surface immersed in liquid media; thus, it has been considered to be an indispensable tool for nanobiotechnology and is used in many research fields, including molecular biology and surface science. For real-time observation of a certain behavior, the high speed imaging technique should be accompanied with a high resolution imaging technique to identify target materials. To improve the image quality at a high scanning rate, we developed a variable-controlled fast scanning method, which originated from the modified squeeze-drag superposition model in liquid media. A collection of non-distorted images was accomplished after proper modification of the operating conditions in a viscous fluid, via the simple handling of loading force and cantilever length. Consequently, a speeded-up AFM imaging process was achieved in the liquid environment at up to 200 µm s(-1), without attachment of additional devices. The reliability of the proposed method was verified by the characterization of a grating sample immersed in three types of liquid media. In addition, the results were visualized for elastic biomolecules submerged in a liquid with high kinematic viscosity.

Reversible pH-driven conformational switching of tethered superoxide dismutase with gold nanoparticle enhanced surface plasmon resonance spectroscopy.

A new class of surface-immobilized protein nanomachines can be reversibly actuated by cycling the solution pH between 2.5 and 12.3, which induces a conformational change, thereby modulating the thickness of superoxide dismutase (SOD1) tethered to the Au thin film. By placing Au nanoparticles (AuNP) atop the immobilized SOD1 by means of a gold-thiol assembly, the nanoscale motion of SOD1 at the interface produces mechanical work to lift and then lower the AuNP from the Au substrate by a distance of ca. 3 nm and transduces this motion into an easily measurable reflectivity change in the surface plasmon resonance (SPR) spectrum. As-made supported conjugate consisting of SOD1 and AuNP is quite robust and stable, and its operation in response to pH variations, which mirrors the conformational changes of responsive SOD1 at the interface, is found to be highly reversible and reproducible. This is the first demonstration of the development of novel solid-state sensors and/or switching devices based on substrate-bound protein conformational changes and AuNP enhanced SPR spectroscopy.