A photoinduced nanoparticle separation in microchannels via pH-sensitive surface traps

Temperature Responsive Polymer Conjugate Prepared by "Grafting from" Proteins toward the Adsorption and Removal of Uremic Toxin

In this study, temperature-responsive polymer-protein conjugate was synthesized using a “grafting from” concept by introducing a chain transfer agent (CTA) into bovine serum albumin (BSA). The BSA-CTA was used as a starting point for poly(N-isopropylacrylamide) (PNIPAAm) through reversible addition-fragmentation chain transfer polymerization. The research investigations suggest that the thermally responsive behavior of PNIPAAm was controlled by the monomer ratio to CTA, as well as the amount of CTA introduced to BSA. The study further synthesized the human serum albumin (HSA)-PNIPAAm conjugate, taking the advantage that HSA can specifically adsorb indoxyl sulfate (IS) as a uremic toxin. The HSA-PNIPAAm conjugate could capture IS and decreased the concentration by about 40% by thermal precipitation. It was also revealed that the protein activity was not impaired by the conjugation with PNIPAAm. The proposed strategy is promising in not only removal of uremic toxins but also enrichment of biomarkers for early diagnostic applications.

Thermo-responsive polymers and their application as smart biomaterials

This review summarises smart thermo-responsive polymeric materials with reversible and ‘on–off’ remotely switchable properties for a wide range of biomedical and biomaterials applications.

Advancements in microfluidics for nanoparticle separation

Nanoparticles have been widely implemented for healthcare and nanoscience industrial applications. Thus, efficient and effective nanoparticle separation methods are essential for advancement in these fields. However, current technologies for separation, such as ultracentrifugation, electrophoresis, filtration, chromatography, and selective precipitation, are not continuous and require multiple preparation steps and a minimum sample volume. Microfluidics has offered a relatively simple, low-cost, and continuous particle separation approach, and has been well-established for micron-sized particle sorting. Here, we review the recent advances in nanoparticle separation using microfluidic devices, focusing on its techniques, its advantages over conventional methods, and its potential applications, as well as foreseeable challenges in the separation of synthetic nanoparticles and biological molecules, especially DNA, proteins, viruses, and exosomes.

Phototriggered release of amine from a cucurbituril macrocycle

Amines are released from a cucurbituril macrocycle by photoinduced pH jump and modulation of the competitiveness of a fluorescent guest.

Inactivated Sendai Virus (HVJ-E) Immobilized Electrospun Nanofiber for Cancer Therapy

Inactivated Hemagglutinating Virus of Japan Envelope (HVJ-E) was immobilized on electrospun nanofibers of poly(ε-caprolactone) by layer-by-layer (LbL) assembly technique. The precursor LbL film was first constructed with poly-L-lysine and alginic acid via electrostatic interaction. Then the HVJ-E particles were immobilized on the cationic PLL outermost surface. The HVJ-E adsorption was confirmed by surface wettability test, scanning laser microscopy, scanning electron microscopy, and confocal laser microscopy. The immobilized HVJ-E particles were released from the nanofibers under physiological condition. In vitro cytotoxic assay demonstrated that the released HVJ-E from nanofibers induced cancer cell deaths. This surface immobilization technique is possible to perform on anti-cancer drug incorporated nanofibers that enables the fibers to show chemotherapy and immunotherapy simultaneously for an effective eradication of tumor cells in vivo.

Improving lateral-flow immunoassay (LFIA) diagnostics via biomarker enrichment for mHealth

Optical detection technologies based on mobile devices can be utilized to enable many mHealth applications, including a reader for lateral-flow immunoassay (LFIA). However, an intrinsic challenge associated with LFIA for clinical diagnostics is the limitation in sensitivity. Therefore, rapid and simple specimen processing strategies can directly enable more sensitive LFIA by purifying and concentrating biomarkers. Here, a binary reagent system is presented for concentrating analytes from a larger volume specimen to improve the malaria LFIA's limit of detection (LOD). The biomarker enrichment process utilizes temperature-responsive gold-streptavidin conjugates, biotinylated antibodies, and temperature-responsive magnetic nanoparticles. The temperature-responsive gold colloids were synthesized by modifying the citrate-stabilized gold colloids with a diblock copolymer, containing a thermally responsive poly(N-isopropylacrylamide) (pNIPAAm) segment and a gold-binding block composed of NIPAAm-co-N,N-dimethylaminoethylacrylamide. The gold-streptavidin conjugates were synthesized by conjugating temperature-responsive gold colloids with streptavidin via covalent linkages using carbodiimide chemistry chemistry. The gold conjugates formed half-sandwiches, gold labeled biomarker, by complexing with biotinylated antibodies that were bound to Plasmodium falciparum histidine-rich protein 2 (PfHRP2), a malaria antigen. When a thermal stimulus was applied in conjunction with a magnetic field, the half-sandwiches and temperature-responsive magnetic nanoparticles that were both decorated with pNIPAAm formed large aggregates that were efficiently magnetically separated from human plasma. The binary reagent system was applied to a large volume (500 μL) specimen for concentrating biomarker 50-fold into a small volume and applied directly to an off-the-shelf malaria LFIA to improve the signal-to-noise ratio.