Biological Safety Testing Research Articles

Sustainable Primary Cell Banking for Topical Compound Cytotoxicity Assays: Protocol Validation on Novel Biocides and Antifungals for Optimized Burn Wound Care

Thorough biological safety testing of topical therapeutic compounds and antimicrobials is a critical prerequisite for appropriate cutaneous wound care. Increasing pathogen resistance rates to traditional antibiotics and antifungals are driving the development and registration of novel chemical entities. Although they are notably useful for animal testing reduction, the gold standard in vitro cytotoxicity assays in continuous cell lines (HaCaT keratinocytes, 3T3 fibroblasts) may be discussed from a translational relevance standpoint. The aim of this study was thus to establish and validate a sustainable primary cell banking model with a view to performing optimized in vitro cytotoxicity assay development. Primary dermal fibroblasts and adipose-derived stem cell (ASC) types were established from four infant polydactyly sources. A multi-tiered primary cell banking model was then applied to prepare highly sustainable and standardized dermal fibroblast and ASC working cell banks (WCBs), potentially allowing for millions of biological assays to be performed. The obtained cellular materials were then validated for use in cytotoxicity assays through in vitro biosafety testing of topical antiseptics (chlorhexidine, hypochlorous acid) and an antifungal compound (AR-12) of interest for optimized burn wound care. The experimental results confirmed that IC50 values were comparable between cytotoxicity assays, which were performed with cell lines and with primary cells. The results also showed that hypochlorous acid (HOCl) displayed an enhanced toxicological profile as compared to the gold standard chlorhexidine (CLX). Generally, this study demonstrated that highly sustainable primary cell sources may be established and applied for consistent topical compound biological safety assessments with enhanced translational relevance. Overall, the study underscored the safety-oriented interest of functionally benchmarking the products that are applied on burn patient wounds for the global enhancement of burn care quality.

Activation and stabilization of the Cu species via strong CuO-CeO2 interactions for enhanced decomposition of refractory aromatic organic pollutants in water

The copper (Cu)-driven advanced oxidation process (AOP) represents one green and efficient technology for the removal of refractory aromatic organic pollutants from water. However, its application remained challenged by the sluggish regeneration of the active Cu+ species and the environmental risk induced by Cu leaching. Herein we reported a facile approach to the bimetallic composite CuCeOx-A catalyst with strong CuO-CeO2 interactions (“A” referred to the acid-activation process). It enabled a TOC removal efficiency (δ%) of 92.4 % and a turnover frequency (TOF) of 1.57 min−1 for TOC removal from 100 mg/L 2-naphthol aqueous solution, outperforming the CuO (δ% = 82.9 % and TOF = 0.23 min−1) and most of the reported Cu-based catalysts. It was more active under neutral/weakly acidic conditions, and could keep high performances in a wide 2-NAP concentration window and in the presence of some impurity ions (PO43-, NH4+ or SiO32-). Additionally, the Cu leaching of CuCeOx-A maintained at a much lower level of ∼ 1.0 ± 0.2 mg/L than that of CuO (∼12.8 ± 1.9 mg/L). Mechanistic studies demonstrated that the enhanced AOP performance and chemical stability of CuCeOx-A originated from the strong CuO-CeO2 interactions, which facilitated the Cu+ regeneration by up-lifting the redox potential of Cu2+/Cu+ and stabilized Cu species via the Cu–O-Ce bonds. Further biological safety testing using chlorella cells as probe organism revealed that the CuCeOx-A-driven AOP was environmentally benign for aromatic organic pollutants removal.

Research Highlights.

Research Highlights.

Natural rosin modified carboxymethyl cellulose delivery system with lowered toxicity for long-term pest control

The increasing world-wide demand for food has prompted the development of efficient and environmentally friendly pesticide formulations. In this article, we have prepared CMC-g-PRSG carrier based on two compounds from natural materials carboxymethyl cellulose (CMC) and rosin (RS). The model pesticide avermectin (AVM) was encapsulated through hydrophobic interaction, and self-assembled to form nanopesticide AVM@CMC-g-PRSG with an average particle size of 167 nm. The prepared nanopesticide displays enhanced dispersibility and stability of AVM in water, and can effectively adhere to the leaves to prevent loss. The release rate of AVM encapsulated in the nanocarrier can be controlled by adjusting pH, and AVM half-life under ultraviolet radiation shows a 3-fold increase allowing control of pests for prolonged periods of time in practical applications. Biological safety tests showed that AVM@CMC-g-PRSG effectively reduces the toxicity of AVM to aquatic animals. Therefore, the cheap and degradable carrier CMC-g-PRSG can improve the effect of hydrophobic pesticides.

Biological safety testing: supporting medical device combination products

Biological safety testing: supporting medical device combination products

Faster, Cheaper, Safer, T-cell Engineering

Faster, Cheaper, Safer, T-cell Engineering

The biological activities of (1,3)-(1,6)-β-d-glucan and porous electrospun PLGA membranes containing β-glucan in human dermal fibroblasts and adipose tissue-derived stem cells

In this study, we investigated the possible roles of (1,3)-(1,6)-β-d-glucan (β-glucan) and porous electrospun poly-lactide-co-glycolide (PLGA) membranes containing β-glucan for skin wound healing, especially their effect on adult human dermal fibroblast (aHDF) and adipose tissue-derived stem cell (ADSC) activation, proliferation, migration, collagen gel contraction and biological safety tests of the prepared membrane. This study demonstrated that β-glucan and porous PLGA membranes containing β-glucan have enhanced the cellular responses, proliferation and migration, of aHDFs and ADSCs and the result of a collagen gel contraction assay also revealed that collagen gels contract strongly after 4 h post-gelation incubation with β-glucan. Furthermore, we confirmed that porous PLGA membranes containing β-glucan are biologically safe for wound healing study. These results indicate that the porous PLGA membranes containing β-glucan interacted favorably with the membrane and the topical administration of β-glucan was useful in promoting wound healing. Therefore, our study suggests that β-glucan and porous PLGA membranes containing β-glucan may be useful as a material for enhancing wound healing.

Current Topics in Biological Safety Tests on Foods, Food Additives and Contaminants

Current Topics in Biological Safety Tests on Foods, Food Additives and Contaminants

The Synthetic Plasmodium falciparum Circumsporozoite Peptide PfCS102 as a Malaria Vaccine Candidate: A Randomized Controlled Phase I Trial

BackgroundFully efficient vaccines against malaria pre-erythrocytic stage are still lacking. The objective of this dose/adjuvant-finding study was to evaluate the safety, reactogenicity and immunogenicity of a vaccine candidate based on a peptide spanning the C-terminal region of Plasmodium falciparum circumsporozoite protein (PfCS102) in malaria naive adults.Methodology and Principal FindingsThirty-six healthy malaria-naive adults were randomly distributed into three dose blocks (10, 30 and 100 µg) and vaccinated with PfCS102 in combination with either Montanide ISA 720 or GSK proprietary Adjuvant System AS02A at days 0, 60, and 180. Primary end-point (safety and reactogenicity) was based on the frequency of adverse events (AE) and of abnormal biological safety tests; secondary-end point (immunogenicity) on P. falciparum specific cell-mediated immunity and antibody response before and after immunization. The two adjuvant formulations were well tolerated and their safety profile was good. Most AEs were local and, when systemic, involved mainly fatigue and headache. Half the volunteers in AS02A groups experienced severe AEs (mainly erythema). After the third injection, 34 of 35 volunteers developed anti-PfCS102 and anti-sporozoite antibodies, and 28 of 35 demonstrated T-cell proliferative responses and IFN-γ production. Five of 22 HLA-A2 and HLA-A3 volunteers displayed PfCS102 specific IFN-γ secreting CD8+ T cell responses. Responses were only marginally boosted after the 3rd vaccination and remained stable for 6 months. For both adjuvants, the dose of 10 µg was less immunogenic in comparison to 30 and 100 µg that induced similar responses. AS02A formulations with 30 µg or 100 µg PfCS102 induced about 10-folds higher antibody and IFN-γ responses than Montanide formulations.Conclusions/SignificancePfCS102 peptide was safe and highly immunogenic, allowing the design of more advanced trials to test its potential for protection. Two or three immunizations with a dose of 30 µg formulated with AS02A appeared the most appropriate choice for such studies.Trial RegistrationSwissmedic.ch 2002 DR 1227

Applications of the Polymerase Chain Reaction in Retroviral-Mediated Gene Transfer and the Analysis of Gene-Marked Human TIL Cells

The polymerase chain reaction (PCR), a widely used new technology, was applied to several aspects of retroviral-mediated gene transfer. Ten oligonucleotide primer pairs were analyzed for their ability to amplify specific regions of a retroviral vector, including the long terminal repeat (LTR), and a NeoR selectable marker gene. By using the appropriate oligonucleotide primers, cells transduced by retroviral vectors could readily be detected and analyzed for deletions in proviral sequences by PCR, without Southern blotting. In combination with a simplified RNA isolation/reverse transcription protocol, an approximate titer of vector producer cell lines could be estimated by PCR in a single day, eliminating the need for time-consuming transductions and biological selection. Quantification of data obtained from PCR dilution experiment indicates that, under appropriate conditions, amplification is linear with respect to the amount of input DNA, permitting estimations of gene dosage in unknown samples. Specific PCR procedures have been developed as part of a protocol involving the transfer of retroviral-marked human tumor infiltrating lymphocytes (TIL) to cancer patients undergoing TIL cell cancer therapy. To augment biological safety testing methods, PCR has been used to detect the presence of possible amphotropic helper virus genomes at a sensitivity of one marked cell in 10(5) unmarked cells. The further use of PCR technology in the TIL cell human gene transfer protocol is demonstrated by the ability to detect small numbers of transduced TIL cells in the presence of hundreds of thousands of untransduced TIL.

Notes to applicants for marketing authorizations on the pre-clinical biological safety testing of medicinal products derived from biotechnology (and comparable products derived from chemical synthesis)

Notes to applicants for marketing authorizations on the pre-clinical biological safety testing of medicinal products derived from biotechnology (and comparable products derived from chemical synthesis)

Biological safety tests for the quality control of parenteral pharmaceuticals

Biological safety tests are proposed for parenteral water-soluble drugs and for drugs in oil suspensions. The test dosages are base on the intravenous or intramuscular administration of the drugs in doses which approach or surpass symptomatic doses in the species of animal used. The tests thus aid in detecting serious departure from proper compounding procedures and are suggested as routine control measures in the manufacture of the enumerated drugs.