Photo-induced surface grafting of phosphorylcholine containing copolymers onto mesoporous silica nanoparticles for controlled drug delivery

Preparation of Nonfouling Zwitterionic Coatings by Plasma-Enhanced Chemical Vapor Deposition under Ambient Pressure

Nonspecific protein adsorption significantly impacts the performance of biomedical devices in both hemocompatibility and tissue compatibility. Polyzwitterionic coatings are a promising solution. However, conventional zwitterionic coatings always have to rely on sophisticated wet chemistry methods, leading to low controllability and high cost. In this work, zwitterionic coatings were prepared by nitrogen plasma-enhanced chemical vapor deposition (PECVD) of precursors for 90 s under ambient pressure followed by hydrolysis. The results showed that the PECVD-coated thermoplastic polyurethane (TPU), Tecoflex, effectively resists nonspecific protein adsorption, platelet adhesion, and bacterial adhesion without changing the mechanic properties of TPU. This approach simplified the zwitterionic coating process with highly controllability, showing a promising potential for the surface modification of biomedical devices.

Recent progress and perspectives in applications of 2-methacryloyloxyethyl phosphorylcholine polymers in biodevices at small scales

Bioinspired materials have attracted attention in a wide range of fields. Among these materials, a polymer family containing 2-methacryloyloxyethyl phosphorylcholine (MPC), which has a zwitterionic phosphorylcholine headgroup inspired by the...

Progress in the Free and Controlled Radical Homo- and Co-Polymerization of Itaconic Acid Derivatives: Toward Functional Polymers with Controlled Molar Mass Distribution and Architecture

Polymeric derivatives of itaconic acid are becoming increasingly more interesting for research and industry because itaconic acid is accessible from renewable resources. In spite of the structural similarity of poly(itaconic acid derivatives) to poly(methacrylates), they are much less reactive, homopolymerize only sluggishly by free radical polymerization (FRP), and are often obtained with low molar masses and conversions. This has so far limited their use. The reasons for the low reactivity of itaconic acid derivatives (including itaconimides, diitaconates, and diitaconamides) are combined steric and electronic effects, as demonstrated by the body of literature on the FRP homopolymerization kinetics of these monomers which is summarized herein. These problems can be solved to a large extent by using controlled radical polymerization (CRP) techniques, notably atom transfer radical polymerization (ATRP) and reversible addition and fragmentation chain transfer radical polymerization (RAFT). By optimizing the reaction conditions for the ATRP and RAFT of itaconic acid derivatives, in particular the reaction temperature, linear relations between molar mass and conversion are obtained in many cases, and homopolymers with high molar masses and reasonably narrow polydispersity indices become accessible. This review presents the state-of-the-art FRP and CRP of itaconic acid derivatives, and highlights functional polymers obtained by these methods.

Universal Strategy for Efficient Fabrication of Blood Compatible Surfaces via Polydopamine-Assisted Surface-Initiated Activators Regenerated by Electron Transfer Atom-Transfer Radical Polymerization of Zwitterions

Implant and blood-contacting biomaterials are challenged by biofouling and thrombus formation at their interface. Zwitterionic polymer brush coating can achieve excellent hemocompatibility, but the preparation often involves tedious, expensive, and complicated procedures that are designed for specific substrates. Here, we report a facile and universal strategy of creating zwitterionic polymer brushes on variety of materials by polydopamine (PDA)-assisted and surface-initiated activators regenerated by electron transfer atom-transfer radical polymerization (PDA-SI-ARGET-ATRP). A PDA adhesive layer is first dipcoated on a substrate, followed by covalent immobilization of 3-trimethoxysilyl propyl 2-bromo-2-methylpropionate (SiBr, ATRP initiator) on the PDA via condensation. Meanwhile, the trimethoxysilyl group of SiBr also cross-links the PDA oligomers forming stabilized PDA/SiBr complex coating. Finally, SI-ARGET-ATRP is performed in a zwitterionic monomer solution catalyzed by the parts per million level of CuBr₂ without deoxygenization. The conveniently fabricated zwitterionic polymer brush coatings are demonstrated to have stable, ultralow fouling, and extremely blood compatible and functionalizable characteristics. This facile, versatile, and universal surface modification strategy is expected to be widely applicable in various advanced biomaterials and devices.

Recent development and prospects of surface modification and biomedical applications of MXenes

MXenes, as a novel kind of two-dimensional (2D) materials, were first discovered by Gogotsi et al. in 2011. Owing to their multifarious chemical compositions and outstanding physicochemical properties, the novel types of 2D materials have attracted intensive research interest for potential applications in various fields such as energy storage and conversion, environmental remediation, catalysis, and biomedicine. Although many achievements have been made in recent years, there still remains a lack of reviews to summarize these recent advances of MXenes, especially in biomedical fields. Understanding the current status of surface modification, biomedical applications and toxicity of MXenes and related materials will give some inspiration to the development of novel methods for the preparation of multifunctional MXene-based materials and promote the practical biomedical applications of MXenes and related materials. In this review, we present the recent developments in the surface modification of MXenes and the biomedical applications of MXene-based materials. In the first section, some typical surface modification strategies were introduced and the related issues were also discussed. Then, the potential biomedical applications (such as biosensor, biological imaging, photothermal therapy, drug delivery, theranostic nanoplatforms, and antibacterial agents) of MXenes and related materials were summarized and highlighted in the following sections. In the last section, the toxicity and biocompatibility of MXenes in vitro were mentioned. Finally, the development, future directions and challenges about the surface modification of MXene-based materials for biomedical applications were discussed. We believe that this review article will attract great interest from the scientists in materials, chemistry, biomedicine and related fields and promote the development of MXenes and related materials for biomedical applications.

The combination of Diels-Alder reaction and redox polymerization for preparation of functionalized CNTs for intracellular controlled drug delivery

Carbon nanotubes (CNTs) are a novel type of one-dimensional carbon nanomaterials that have been widely utilized for biomedical applications such as drug delivery, cancer photothermal treatment owing to their high surface area and unique interaction with cell membranes. However, their biomedical applications are still impeded by some drawbacks, including poor water dispersibility, lack of functional groups and toxicity. Therefore, surface modification of CNTs to overcome these issues should be importance and of great interest. In this work, we reported for the first time that CNTs could be surface modification through the combination of Diels-Alder (D-A) reaction and redox polymerization, this strategy shows the advantages of mild reaction conditions, water tolerance, low temperature and hydroxyl-surfaced initiator. In this modification procedure, the hydroxyl groups were introduced on the surface of CNTs through the D-A reaction that was adopted for grafting the copolymers, which were initiated by the Ce(IV)/HNO₃ redox system using the hydrophilic and biocompatible poly(ethylene glycol) methyl ether methacrylate (PEGMA) and carboxyl-rich acrylic acid (AA) as monomers. The final CNTs-OH-PAA@PEGMA composites were characterized by a series of characterization techniques. The drug loading and release results suggested that anticancer agent cis‑platinum (CDDP) could be loaded on CNTs-OH-PAA@PEGMA composites through coordination with carboxyl groups and drug release behavior could be controlled by pH. More importantly, the cell viability results clearly demonstrated that CNTs-OH-PAA@PEGMA composites displayed low toxicity and the drug could be transported in cells and still maintain their therapeutic effects.

Utilization of lithium incorporated mesoporous silica for preventing necrosis and increase apoptosis in different cancer cells

There are many molecules used as a drug carrier. TUD-1 is a newly synthesized mesoporous silica (SM) molecule possess two important features; consists of mesoporous so it is very suitable to be drug carrier in addition to that it has the ability to induce apoptosis in cancer cells. However, the effect of TUD-1 appears to act as cell death inducer, regardless of whether it is necrosis or apoptosis. Unfortunately, recent studies indicate that a proportion of cells undergo necrosis rather than apoptosis, which limits the use of TUD-1 as a secure treatment. On the other hand, lithium considered as necrosis inhibitor element. Hence, the current study based on the idea of producing a new Li-TUD-1 by incorporated mesoporous silica (TUD-1 type) with lithium in order to produce a new compound that has the ability to activate apoptosis by mesoporous silica (TUD-1 type) and at the same time can inhibit the activity of necrosis by lithium. Herein, lithium incorporated in TUD-1 mesoporous silica by using sol-gel technique in one-step synthesis procedure. Moreover, lithium incorporated in TUD-1 with different loading in order to form different active sites such as isolated lithium ions, nanoparticles of Li₂O, and bulky crystals of Li₂O. The ability of the new compounds to induce apoptosis and prevent necrosis was evaluated on three different types of cancer cell lines, which are; liver HepG-2, breast MCF-7, and colon HCT116. The obtained results show that Li-TUD-1 has the ability to control necrosis and thus reduce the side effects of treatments containing silica in the case of lithium added to them, especially in chronic cases. This opinion has demonstrated by the significant increase in the IC₅₀ value and cell viability compared to control groups. Consequently, the idea is new, so it needs more develop and test with materials that have a more apoptotic impact than silica to induce apoptosis without induction of necrosis.

Phytocosmeceutical formulation development, characterization and its in-vivo investigations

Several plants found rich in flavonoid, polyphenols, and antioxidants reported antiaging, oppose inflammation and carcinogenic properties but have rarely been applied in dermatology. The present study was an active attempt to formulate a stable phytocosmetic emulsion system loaded with 2% pre-concentrated Prosopis cineraria bark extract, aiming to revive facial skin properties. In order to obtain potent therapeutic activities, we first prepared extracts of stem, leaves, and bark and screen them on basis of phenolic, flavonoids contents and antioxidant, antibacterial, lipoxygenase and tyrosinase inhibition activities. Furthermore, cytocompatibility of the extract was also determined prior starting in vivo investigations. Then the in vivo performance of 2% bark extract loaded emulsion formulation was determined by using non-invasive probe cutometer and elastometer with comparison to base formulation. The preliminary experiment showed that bark extract has a significant amount of phenolic and flavonoid compounds with eminent antioxidant potential. Furthermore, indicated an efficient antibacterial, lipoxygenase, and tyrosinase enzyme inhibition activities. Importantly, the bark extract did not induce any toxicity or apoptosis, when incubated with HaCat cells. Moreover, the in vivo results showed the formulation (size 3 μm) decreased the skin melanin, erythema and sebum contents up to 2.1-,2.7-and 79%, while increased the skin hydration and elasticity up to 2-folds and 22% as compared to the base, respectively. Owing to enhanced therapeutic effects the phytocosmetic formulation proved to be a potential skin whitening, moisturizer, anti-acne, anti-wrinkle, anti-aging therapy and could actively induce skin rejuvenation and resurfacing.

One-pot ultrafast preparation of silica quantum dots and their utilization for fabrication of luminescent mesoporous silica nanoparticles

Silica quantum dots (SiQDs) and their luminescent composites have displayed great potential for biomedical applications owing to their chemical inert and low cost. In this work, we report a facile, cost-effective and ultrafast strategy to prepare a stable luminescent SiQDs using N-[3-(trimethoxysilyl)propyl]ethylenediamine (EDAS) and salicylaldehyde as precursors for the first time. These luminescent SiQDs were further utilized for fabrication of luminescent mesoporous silica nanoparticles (MSNs) through direct encapsulation of SiQDs by MSNs. The novel synthetic and modified SiQDs uses commercial raw materials and the entire reaction can be completed within 30 s. The successful preparation of SiQDs and SiQDs@MSNs were characterized by various characterization equipments. The cell viability as well as cell uptake behavior of SiQDs@MSNs were also examined to evaluate their potential for biomedical applications. We demonstrated that these SiQDs@MSNs are low toxicity and of great potential for biological imaging. Based on the above results, we believe that these SiQDs@MSNs should be novel and promising candidates for biomedical applications owing to their intense fluorescence, biocompatibility and high specific surface areas.

Surface grafting of rare-earth ions doped hydroxyapatite nanorods (HAp:Ln(Eu/Tb)) with hydrophilic copolymers based on ligand exchange reaction: Biological imaging and cancer treatment

Rare-earth ions doped hydroxyapatite nanoparticles (HAp:Ln NPs) have demonstrated to be very promising candidates for biological imaging applications owing to their small size and chemical compositions similar to bone. However, these HAp:Ln NPs with controllable size and morphology should be prepared under hydrothermal treatment with hydrophobic molecules as the protective layers. The hydrophobic nature of these luminescent HAp:Ln NPs largely impeded their applications in biomedical fields. In this study, a novel and effective strategy has been developed for the surface modification of HAp:Ln nanorods through the combination of surface ligand exchange reaction and reversible-addition fragmentation chain transfer (RAFT) polymerization using 2-methacryloyloxyethyl phosphorylcholine (MPC) and itaconic acid (IA) as the monomers. Herein, a small molecule adenosine 5'-monophosphate disodium salt (AMP) that contains a phosphate group and two hydroxyl groups was used to displace the hydrophobic oleic acid on pristine HAp NPs through surface ligand exchange reaction owing to its stronger interaction with HAp NPs. On the other hand, the MPC and IA were introduced on HAp NPs through RAFT polymerization after the chain transfer agent was immobilized on the HAp NPs through the esterification reaction. The poly(IA-MPC) could not only endow the high water dispersibility but also be used for loading anticancer agent cisplatin (CDDP) through coordination interaction. To evaluate their potential biomedical applications, the cell uptake behavior, drug loading capacity and release behavior as well as cell viability of HAp:Ln-AMP-poly(IA-MPC) polymeric composites were examined. We demonstrated that the method developed in this work is very effective for introduction of functional polymers onto HAp:Ln nanorods. The HAp:Ln-AMP-poly(IA-MPC) composites are promising for cell imaging and controlled delivery of CDDP.

A biomimetic fluorescent chemosensor for highly sensitive zinc(ii) detection and its application for cell imaging

To fabricate a novel biomimetic fluorescent chemosensor, PSaAEMA-co-PMPC was synthesized via atom transfer radical polymerization, and this copolymer could be used for the detection of zinc(ii) and cell imaging. A series tests with various metal ions verified the specific fluorescence response behavior. This novel biomimetic fluorescent chemosensor exhibits excellent selectivity for Zn²⁺ ions over a wide range of tested metal ions in an aqueous solution. Moreover, cytotoxicity and bio-imaging tests were conducted to study the potential bio-application of the chemosensor. Owing to the biomimetic portion (phosphorylcholine), this copolymer possesses outstanding biocompatibility and could clearly image cells. The results indicated that PSaAEMA-co-PMPC has great potential for application in zinc(ii) detection and cell imaging.

To fabricate a novel biomimetic fluorescent chemosensor, PSaAEMA-co-PMPC was synthesized via atom transfer radical polymerization, and this copolymer could be used for the detection of zinc(ii) and cell imaging.