Bacillus subtilis SOM8 isolated from sesame oil meal for potential probiotic application in inhibiting human enteropathogens.

BACKGROUND: While particular strains within the Bacillus species, such as Bacillus subtilis, have been commercially utilised as probiotics, it is critical to implement screening assays and evaluate the safety to identify potential Bacillus probiotic strains before clinical trials. This is because some Bacillus species, including B. cereus and B. anthracis, can produce toxins that are harmful to humans. RESULTS: In this study, we implemented a funnel-shaped approach to isolate and evaluate prospective probiotics from homogenised food waste - sesame oil meal (SOM). Of nine isolated strains with antipathogenic properties, B. subtilis SOM8 displayed the most promising activities against five listed human enteropathogens and was selected for further comprehensive assessment. B. subtilis SOM8 exhibited good tolerance when exposed to adverse stressors including acidity, bile salts, simulated gastric fluid (SGF), simulated intestinal fluid (SIF), and heat treatment. Additionally, B. subtilis SOM8 possesses host-associated benefits such as antioxidant and bile salt hydrolase (BSH) activity. Furthermore, B. subtilis SOM8 contains only haemolysin toxin genes but has been proved to display partial haemolysis in the test and low cytotoxicity in Caco-2 cell models for in vitro evaluation. Moreover, B. subtilis SOM8 intrinsically resists only streptomycin and lacks plasmids or other mobile genetic elements. Bioinformatic analyses also predicted B. subtilis SOM8 encodes various bioactives compound like fengycin and lichendicin that could enable further biomedical applications. CONCLUSIONS: Our comprehensive evaluation revealed the substantial potential of B. subtilis SOM8 as a probiotic for targeting human enteropathogens, attributable to its exceptional performance across selection assays. Furthermore, our safety assessment, encompassing both phenotypic and genotypic analyses, showed B. subtilis SOM8 has a favourable preclinical safety profile, without significant threats to human health. Collectively, these findings highlight the promising prospects of B. subtilis SOM8 as a potent probiotic candidate for additional clinical development.

Synthesis of Polymeric Janus Superstructures via a Facile Synthesis Method.

Polymeric Janus particles can be exploited for a myriad of applications. Through the understanding of interfacial tensions, theragnostic agents such as drugs or nanomaterials can be successfully encapsulated into Janus particles without losing their anisotropic structure. In this work, it is reported that how Janus superstructures, as a further extension of the Janus morphology, can be obtained by blending other synthesis parameters into the solvent emulsion process, while adhering to the requirements of the Harkin's spreading coefficient (HSC) theory. Designing such unique structures for drug delivery can provide a broader range of possibilities and applications beyond conventional Janus particles.

Hybrid Janus Microparticles Achieving Selective Encapsulation for Theranostic Applications via a Facile Solvent Emulsion Method.

Anisotropic Janus particles composed of biocompatible polymers have been gaining considerable interest for biomedical applications. Here, the fabrication of hybrid Janus particles via a single-step solvent emulsion technique, potentially for theranostic purposes, is shown. Through this technique, the selective encapsulation of therapeutic and diagnostic agents is streamlined into different "faces" of the Janus structure. This facile technique is used to seamlessly fabricate polymeric-based hybrid Janus particles for theranostic applications with little complexity.

Hollow Microparticles as a Superior Delivery System over Solid Microparticles for the Encapsulation of Peptides.

PURPOSE: Peptides are gaining significant interests as therapeutic agents due to their high targeting specificity and potency. However, their low bioavailability and short half-lives limit their massive potential as therapeutics. The use of dense, solid particles of biodegradable polymer as a universal carrier for peptides also has its challenges, such as inefficient peptide release and low bioactivity. In this paper, it was established that hollow microparticles (h-MPs) instead of solid microparticles (s-MPs), as peptide carriers, could improve the release efficiency, while better preserving their bioactivity. METHODS: Glucagon like Peptide-1 (GLP-1) was encapsulated as a model peptide. Mass loss, average molecular weight changes, intraparticle pH, polymer-peptide interaction and release studies, together with bioactivity assessment of the peptide for s-MPs and h-MPs were systematically analyzed and evaluated for efficacy. RESULTS: The intraparticle pH of s-MPs was as low as 2.64 whereas the pH of h-MPs was 4.99 by day 7. Consequently, 93% of the peptide extracted from h-MPs was still bioactive while only 58% of the peptide extracted from s-MPs was bioactive. Likewise, the cumulative release of GLP-1 by day 14 from h-MPs showed a cumulative amount of 88 ± 8% as compared to 33 ± 6% for s-MPs. CONCLUSIONS: The cumulative release of peptide can be significantly improved, and the bioactivity can be better preserved by simply using h-MPs instead of s-MPs as carriers.

Preservation of Anticancer and Immunosuppressive Properties of Rapamycin Achieved Through Controlled Releasing Particles.

Rapamycin is commonly used in chemotherapy and posttransplantation rejection suppression, where sustained release is preferred. Conventionally, rapamycin has to be administered in excess due to its poor solubility, and this often leads to cytotoxicity and undesirable side effects. In addition, rapamycin has been shown to be hydrolytically unstable, losing its bioactivity within a few hours. The use of drug delivery systems is hypothesized to preserve the bioactivity of rapamycin, while providing controlled release of this otherwise potent drug. This paper reports on the use of microparticles (MP) as a means to tune and sustain the delivery of bioactive rapamycin for up to 30 days. Rapamycin was encapsulated (100% efficiency) in poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), or a mixture of both via an emulsion method. The use of different polymer types and mixture was shown to achieve a variety of release kinetics and profile. Released rapamycin was subsequently evaluated against breast cancer cell (MCF-7) and human lymphocyte cell (Jurkat). Inhibition of cell proliferation was in good agreement with in vitro release profiles, which confirmed the intact bioactivity of rapamycin. For Jurkat cells, the suppression of cell growth was proven to be effective up to 20 days, a duration significantly longer than free rapamycin. Taken together, these results demonstrate the ability to tune, sustain, and preserve the bioactivity of rapamycin using MP formulations. The sustained delivery of rapamycin could lead to better therapeutic effects than bolus dosage, at the same time improving patient compliance due to its long-acting duration.

Multi-Drug-Loaded Microcapsules with Controlled Release for Management of Parkinson's Disease.

Parkinson's disease (PD) is a progressive disease of the nervous system, and is currently managed through commercial tablets that do not sufficiently enable controlled, sustained release capabilities. It is hypothesized that a drug delivery system that provides controlled and sustained release of PD drugs would afford better management of PD. Hollow microcapsules composed of poly-l-lactide (PLLA) and poly (caprolactone) (PCL) are prepared through a modified double-emulsion technique. They are loaded with three PD drugs, i.e., levodopa (LD), carbidopa (CD), and entacapone (ENT), at a ratio of 4:1:8, similar to commercial PD tablets. LD and CD are localized in both the hollow cavity and PLLA/PCL shell, while ENT is localized in the PLLA/PCL shell. Release kinetics of hydrophobic ENT is observed to be relatively slow as compared to the other hydrophilic drugs. It is further hypothesized that encapsulating ENT into PCL as a surface coating onto these microcapsules can aid in accelerating its release. Now, these spray-coated hollow microcapsules exhibit similar release kinetics, according to Higuchi's rate, for all three drugs. The results suggest that multiple drug encapsulation of LD, CD, and ENT in gastric floating microcapsules could be further developed for in vivo evaluation for the management of PD.

Inhibition of 3-D tumor spheroids by timed-released hydrophilic and hydrophobic drugs from multilayered polymeric microparticles.

First-line cancer chemotherapy necessitates high parenteral dosage and repeated dosing of a combination of drugs over a prolonged period. Current commercially available chemotherapeutic agents, such as Doxil and Taxol, are only capable of delivering single drug in a bolus dose. The aim of this study is to develop dual-drug-loaded, multilayered microparticles and to investigate their antitumor efficacy compared with single-drug-loaded particles. Results show hydrophilic doxorubicin HCl (DOX) and hydrophobic paclitaxel (PTX) localized in the poly(dl-lactic-co-glycolic acid, 50:50) (PLGA) shell and in the poly(l-lactic acid) (PLLA) core, respectively. The introduction of poly[(1,6-bis-carboxyphenoxy) hexane] (PCPH) into PLGA/PLLA microparticles causes PTX to be localized in the PLLA and PCPH mid-layers, whereas DOX is found in both the PLGA shell and core. PLGA/PLLA/PCPH microparticles with denser shells allow better control of DOX release. A delayed release of PTX is observed with the addition of PCPH. Three-dimensional MCF-7 spheroid studies demonstrate that controlled co-delivery of DOX and PTX from multilayered microparticles produces a greater reduction in spheroid growth rate compared with single-drug-loaded particles. This study provides mechanistic insights into how distinctive structure of multilayered microparticles can be designed to modulate the release profiles of anticancer drugs, and how co-delivery can potentially provide better antitumor response.

Biophysical responses upon the interaction of nanomaterials with cellular interfaces.

The explosion of study of nanomaterials in biological applications (the nano-bio interface) can be ascribed to nanomaterials' growing importance in diagnostics, therapeutics, theranostics (therapeutic diagnostics), and targeted modulation of cellular processes. However, a growing number of critics have raised concerns over the potential risks of nanomaterials to human health and safety. It is essential to understand nanomaterials' potential toxicity before they are tested in humans. These risks are complicated to unravel, however, because of the complexity of cells and their nanoscale macromolecular components, which enable cells to sense and respond to environmental cues, including nanomaterials. In this Account, we explore these risks from the perspective of the biophysical interactions between nanomaterials and cells. Biophysical responses to the uptake of nanomaterials can include conformational changes in biomolecules like DNA and proteins, and changes to the cellular membrane and the cytoskeleton. Changes to the latter two, in particular, can induce changes in cell elasticity, morphology, motility, adhesion, and invasion. This Account reviews what is known about cells' biophysical responses to the uptake of the most widely studied and used nanoparticles, such as carbon-based, metal, metal-oxide, and semiconductor nanomaterials. We postulate that the biophysical structure impairment induced by nanomaterials is one of the key causes of nanotoxicity. The disruption of cellular structures is affected by the size, shape, and chemical composition of nanomaterials, which are also determining factors of nanotoxicity. Currently, popular nanotoxicity characterizations, such as the MTT and lactate dehydrogenase (LDH) assays, only provide end-point results through chemical reactions. Focusing on biophysical structural changes induced by nanomaterials, possibly in real-time, could deepen our understanding of the normal and altered states of subcellular structures and provide useful perspective on the mechanisms of nanotoxicity. We strongly believe that biophysical properties of cells can serve as novel and noninvasive markers to evaluate nanomaterials' effect at the nano-bio interface and their associated toxicity. Better understanding of the effects of nanomaterials on cell structures and functions could help identify the required preconditions for the safe use of nanomaterials in therapeutic applications.

Nanoporous thermochromic VO2 (M) thin films: controlled porosity, largely enhanced luminous transmittance and solar modulating ability.

Vanadium dioxide is the most widely researched thermochromic material with a phase transition temperature (τ(c)) of around 68 °C, and its thermochromic performance can be enhanced by adding nanoporosity. Freeze-drying has been employed to fabricate nanostructures with different porosities from 16 to 45% by varying the prefreezing temperature and precursor concentration. The luminous transmittance (Tlum) and solar modulating ability (ΔTsol) are greatly enhanced as a result of increasing pore size and pore density. The freeze-dried sample with 7.5 mL of H2O2 precursor dip-coated at 300 mm/min gives the best combination of thermochromic properties (Tlum ≈ 50%, ΔTsol = 14.7%), which surpasses the best combined thermochromic performance reported to date that we are aware of (Tlum ≈ 41%, ΔTsol = 14.1%).

Modeling cell membrane perturbation by molecules designed for transmembrane electron transfer.

Certain conjugated oligoelectrolytes (COEs) modify biological function by improving charge transfer across biological membranes as demonstrated by their ability to boost performance in bioelectrochemical systems. Molecular level understanding of the nature of the COE/membrane interactions is lacking. Thus, we investigated cell membrane perturbation by three COEs differing in the number of aromatic rings and presence of a fluorine substitution. Molecular dynamic simulations showed that membrane deformation by all COEs resulted from membrane thinning as the lipid phosphate heads were drawn toward the center of the bilayer layer by positively charged COE side chains. The four-ringed COE, which most closely resembled the lipid bilayer in length, deformed the membrane the least and was least disruptive, as supported by toxicity testing (minimum inhibitory concentration (MIC) = 64 µmol L(-1)) and atomic force microscopy (AFM). Extensive membrane thinning was observed from three-ringed COEs, reducing membrane thickness to <3.0 nm in regions where the COEs were located. Severe localized membrane pitting was observed when the central aromatic ring was unfluorinated, as evident from AFM and simulations. Fluorinating the central aromatic ring delocalized thinning but induced greater membrane disorder, indicated by changes in deuterium order parameter of the acyl chains. The fluorinated three-ringed compound was less toxic (MIC 4 µmol L(-1)) than the nonfluorinated three-aromatic-ringed COE (MIC 2 µmol L(-1)); thus, hydrophobic polar interactions resulting from fluorine substitution of OPV COEs dissipate membrane perturbations. Correlating specific structural features with cell membrane perturbation is an important step toward designing non-antimicrobial membrane insertion molecules.

Membrane permeabilization underlies the enhancement of extracellular bioactivity in Shewanella oneidensis by a membrane-spanning conjugated oligoelectrolyte.

A stilbene-based membrane spanning conjugated oligoelectrolyte 4,4'-bis(4'-N,N-bis(6"-(N,N,N-trimethyl ammonium) hexyl) amino)-styryl) stilbene tetraiodide (DSSN+) has been reported to be able to interact with bacterial cells and enhance their bioelectricity generation in bioelectrochemical devices, although the mechanism remains elusive. The goal of this study was to elucidate the impacts of DSSN+ on extracellular bioactivity and the underlying mechanism. Specifically, extracellular ferrihydrite reduction by Shewanella oneidensis was used to evaluate the influence of cell-DSSN+ interaction. Our results show that DSSN+ enhanced ferrihydrite reduction by S. oneidensis in a growth-dependent manner. The incorporation of DSSN+ into S. oneidensis cell membrane increased the extracellular concentration of redox shuttles, i.e., flavins, and extracellular enzyme activities without significantly decreasing cell viability. The findings suggested that membrane permeabilization is the dominant mechanism for the enhancement of extracellular bioactivity in S. oneidensis by DSSN+. We further demonstrated that the interaction between DSSN+ and S. oneidensis cells enhanced biofilm formation and stability without compromising the overall biofilm activity. Taken together, our results suggest that membrane spanning conjugated oligoelectrolytes, of which DSSN+ is one of many possible molecular structures, may be applied to enhance extracellular bioactivity in bacteria toward more efficient biofilm-based biocatalysis.

A controlled release of antibiotics from calcium phosphate-coated poly(lactic-co-glycolic acid) particles and their in vitro efficacy against Staphylococcus aureus biofilm.

Ceramic-polymer hybrid particles, intended for osteomyelitis treatment, were fabricated by preparing poly(lactic-co-glycolic acid) particles through an emulsion solvent evaporation technique, followed by calcium phosphate (CaP) coating via a surface adsorption-nucleation method. The presence of CaP coating on the surface of the particles was confirmed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Subsequently, two antibiotics for treating bone infection, nafcillin (hydrophilic) and levofloxacin (amphiphilic), were loaded into these hybrid particles and their in vitro drug release studies were investigated. The CaP coating was shown to reduce burst release, while providing sustained release of the antibiotics for up to 4 weeks. In vitro bacterial study against Staphylococcus aureus demonstrated the capability of these antibiotic-loaded hybrid particles to inhibit biofilm formation as well as deteriorate established biofilm, making this hybrid system a potential candidate for further investigation for osteomyelitis treatment.

Utilizing Food Waste in 3D-Printed PLA Formulations to Achieve Sustainable and Customizable Controlled Delivery Systems.

This is the first study that explores blending polylactic acid (PLA) with various biomasses, including food wastes-brewer's spent grain (BSG), spent coffee grounds (SCG), sesame cake (SC), and thermoplastic starch (TPS) biomass to create composite gastric floating drug delivery systems (GFDDS) through 3D printing. The aim is to investigate the influence of biomass percentage, biomass type, and printing parameters on their corresponding drug release profiles. 3D-printed (3DP) composite filaments were prepared by blending biomasses and PLA before in vitro drug release studies were performed using hydrophilic and hydrophobic model drugs, metoprolol tartrate (MT), and risperidone (RIS). The data revealed that release profiles were influenced by composite compositions and wall thicknesses of 3DP GFDDS capsules. Up to 15% of food waste could be blended with PLA for all food waste types tested. Delivery studies for PLA-food wastes found that MT was fully released by 4 h, exhibiting burst release profiles after a lag time of 0.5 to 1.5 h, and RIS could achieve a sustained release profile of approximately 48 h. PLA-TPS was utilized as a comparison and demonstrated variable release profiles ranging from 8 to 120 h, depending on the TPS content. The results demonstrated the potential for adjusting drug release profiles by incorporating affordable biomasses into GFDDS. This study presents a promising direction for creating delivery systems that are sustainable, customizable, and cost-effective, utilizing sustainable materials that can also be employed for agricultural, nutraceutical, personal care, and wastewater treatment applications.

In Vitro Profiling of Potential Fish Probiotics, Enterococcus hirae Strains, Isolated from Jade Perch, and Safety Properties Assessed Using Whole Genome Sequencing.

The demands of intensified aquaculture production and escalating disease prevalence underscore the need for efficacious probiotic strategies to enhance fish health. This study focused on isolating and characterising potential probiotics from the gut microbiota of the emerging aquaculture species jade perch (Scortum barcoo). Eighty-seven lactic acid bacteria and 149 other bacteria were isolated from the digestive tract of five adult jade perch. The screening revealed that 24 Enterococcus hirae isolates inhibited the freshwater pathogens Aeromonas sobria and Streptococcus iniae. Co-incubating E. hirae with the host gut suspensions demonstrated a two- to five-fold increase in the size of growth inhibition zones compared to the results when using gut suspensions from tilapia (a non-host), indicating host-specificity. Genome analysis of the lead isolate, E. hirae R44, predicted the presence of antimicrobial compounds like enterolysin A, class II lanthipeptide, and terpenes, which underlay its antibacterial attributes. Isolate R44 exhibited desirable probiotic characteristics, including survival at pH values within the range of 3 to 12, bile tolerance, antioxidant activity, ampicillin sensitivity, and absence of transferable antimicrobial resistance genes and virulence factors commonly associated with hospital Enterococcus strains (IS16, hylEfm, and esp). This study offers a foundation for sourcing host-adapted probiotics from underexplored aquaculture species. Characterisation of novel probiotics like E. hirae R44 can expedite the development of disease mitigation strategies to support aquaculture intensification.

Chitosan nanofibrous scaffold with graded and controlled release of ciprofloxacin and BMP-2 nanoparticles for the conception of bone regeneration.

The repair of bone defects using grafts is commonly employed in clinical practice. However, the risk of infection poses a significant concern. Tissue engineering scaffolds with antibacterial functionalities offer a better approach for bone tissue repair. In this work, firstly, two kinds of nanoparticles were prepared using chitosan to complex with ciprofloxacin and BMP-2, respectively. The ciprofloxacin complex nanoparticles improved the dissolution efficiency of ciprofloxacin achieving a potent antibacterial effect and cumulative release reached 95 % in 7 h. For BMP-2 complexed nanoparticles, the release time points can be programmed at 80 h, 100 h or 180 h by regulating the number of coating chitosan layers. Secondly, a functional scaffold was prepared by combining the two nanoparticles with chitosan nanofibers. The microscopic nanofiber structure of the scaffold with 27.28 m2/g specific surface area promotes cell adhesion, high porosity provides space for cell growth, and facilitates drug loading and release. The multifunctional scaffold exhibits programmed release function, and has obvious antibacterial effect at the initial stage of implantation, and releases BMP-2 to promote osteogenic differentiation of mesenchymal stem cells after the antibacterial effect ends. The scaffold is expected to be applied in clinical bone repair and graft infection prevention.

Emerging in vitro models for safety screening of high-volume production nanomaterials under environmentally relevant exposure conditions.

The rising production of nanomaterial-based consumer products has raised safety concerns. Testing these with animal and other direct models is neither ethically nor economically viable, nor quick enough. This review aims to discuss the strength of in vitro testing, including the use of 2D and 3D cultures, stem cells, and tissue constructs, etc., which would give fast and repeatable answers of a highly specific nature, while remaining relevant to in vivo outcomes. These results can then be combined and the overall toxicity predicted with relative accuracy. Such in vitro models can screen potentially toxic nanomaterials which, if required, can undergo further stringent studies in animals. The cyto- and phototoxicity of some high-volume production nanomaterials, using in vitro models, is also reviewed.

Evaluating the toxicity of hydroxyapatite nanoparticles in catfish cells and zebrafish embryos.

The toxicity of needle-(nHA-ND) and rod-shaped (nHA-RD) hydroxyapatite (HA) nanoparticles is evaluated in vitro on catfish B-cells (3B11) and catfish T-cells (28s.3) and in vivo on zebrafish embryos to determine if biological effects are similar to the effects seen in mammalian in vitro systems. Neither nHA-ND nor nHA-RD affect cell viability at concentrations of 10 to 300 µg mL(-1) . However, 30 µg mL(-1) needle-shaped nHA lower metabolic activity of the cells. Axial deformations are seen in zebrafish exposed to 300 µg mL(-1) needle shaped nHA after 120 h. For the first time, nHA is reported to cause zebrafish hatching delay. The lowest concentration (3 µg mL(-1) ) of both types of nHA cause the highest hatching inhibition and needle-shaped nHA exposed zebrafish exhibit the lowest hatch at 72 h post fertilization.

Artificial photosynthetic hydrogen evolution over g-C3N4 nanosheets coupled with cobaloxime.

We report an economic and noble-metal-free artificial photosynthetic system, consisting of g-C3N4 as a photosensitizer and a photocatalyst, and cobaloxime as a co-catalyst, for H2 generation. This system allows for effective electron transfer from excited g-C3N4 to Co(III)(dmgH)2pyCl to generate reduced cobaloxime intermediate species for efficient H2 evolution. Transient fluorescence studies reveal that the presence of cobaloxime and TEOA promotes the population of excited electrons to transfer from g-C3N4, which is responsible for the high photocatalytic activity of this g-C3N4-cobaloxime conjugation system.

Cytotoxicity of hydroxyapatite nanoparticles is shape and cell dependent.

Nanosized hydroxyapatite (nHA) has been proposed as drug delivery vehicles because of its biocompatibility. While the possible risks of nHA inducing inflammation have been highlighted, the specific influence of varying nHA particle morphology is still unclear. In order to establish this understanding, nHA of four different shapes--needle (nHA-ND), plate (nHA-PL), sphere (nHA-SP) and rod (nHA-RD)--were synthesized. The particle effects with the concentration of 10-300 µg/mL on cytotoxicity, oxygen species generation, production of inflammatory cytokines (TNF-α and IL-6), particle-cell association and cellular uptake were evaluated on BEAS-2B and RAW264.7 cells. Results show that nHA-ND and nHA-PL induced the most significant cell death in BEAS-2B cultures compared to nHA-SP and nHA-RD. Necrosis-apoptosis assay by FITC Annexin V and propidium iodide (PI) staining revealed loss of the majority of BEAS-2B by necrosis. No significant cell death was recorded in RAW264.7 cultures exposed to any of the nHA groups. Correspondingly, no significant differences were observed in TNF-α level for RAW264.7 cells upon incubation with nHA of different shapes. In addition, nHA-RD exhibited a higher degree of particle-cell association and internalization in both BEAS-2B and RAW264.7 cells, compared to nHA-ND. The phenomena suggested that higher particle-cell association and increased cellular uptake of nHA need not result in increased cytotoxicity, indicating the importance of particle shape on cytotoxicity. Specifically, needle- and plate-shaped nHA induced the most significant cell-specific cytotoxicity and IL-6 expression but showed the least particle-cell association. Taken collectively, we demonstrated the shape-dependent effects of nHA on cytotoxicity, inflammatory cytokine expression and particle-cell association.

Size of TiO(2) nanoparticles influences their phototoxicity: an in vitro investigation.

To uncover the size influence of TiO(2) nanoparticles on their potential toxicity, the cytotoxicity of different-sized TiO(2) nanoparticles with and without photoactivation was tested. It was demonstrated that without photoactivation, TiO(2) nanoparticles were inert up to 100 µg/ml. On the contrary, with photoactivation, the toxicity of TiO(2) nanoparticles significantly increased, which correlated well with the specific surface area of the particles. Our results also suggest that the generation of hydroxyl radicals and reactive oxygen species (ROS)-mediated damage to the surface-adsorbed biomolecules could be the two major reasons for the cytotoxicity of TiO(2) nanoparticles after photoactivation. Higher ROS generation from smaller particles was detected under both biotic and abiotic conditions. Smaller particles could adsorb more proteins, which was confirmed by thermogravimetric analysis. To further investigate the influence of the generation of hydroxyl radicals and adsorption of protein, poly (ethylene-alt-maleic anhydride) (PEMA) and chitosan were used to coat TiO(2) nanoparticles. The results confirmed that surface coating of TiO(2) nanoparticles could reduce such toxicity after photoactivation, by hindering adsorption of biomolecules and generation of hydroxyl radical (·OH) during photoactivation.