Silica Gel

Silica is one of the most abundant minerals in the Earth's crust, and over time it has been introduced first into human life and later into engineering. Silica is present in the food chain and in the human body. As a biomaterial, silica is widely used in dentistry, orthopedics, and dermatology. Recently amorphous sol-gel SiO₂ nanoparticles (NPs) have appeared as nanocarriers in a wide range of medical applications, namely in drug/gene target delivery and imaging diagnosis, where they stand out for their high biocompatibility, hydrophilicity, enormous flexibility for surface modification with a high payload capacity, and prolonged blood circulation time. The sol-gel process is an extremely versatile bottom-up methodology used in the synthesis of silica NPs, offering a great variety of chemical possibilities, such as high homogeneity and purity, along with full scale pH processing. By introducing organic functional groups or surfactants during the sol-gel process, ORMOSIL NPs or mesoporous NPs are produced. Colloidal route, biomimetic synthesis, solution route and template synthesis (the main sol-gel methods to produce monosized silica nanoparticles) are compared and discussed. This short review goes over some of the emerging approaches in the field of non-porous sol-gel silica NPs aiming at medical applications, centered on the syntheses processes used.

This study established an immunoaffinity column for selective extraction of aflatoxins in agri-products. Specifically, the immunoaffinity column was developed by covalently coupling monoclonal antibody 1C11 against aflatoxins to amino-silica gel microparticles and then packing these into a cartridge. The extraction conditions were thoroughly optimized in terms of loading, washing and eluting solutions. Under the optimal conditions, the immunoaffinity column had a capacity of 200 ng of aflatoxins. The detection limits (S/N = 3) for aflatoxin G₁, B₁, G₂ and B₂ were 0.03, 0.07, 0.05 and 0.09 μg·kg⁻¹, and the corresponding quantification limits (S/N = 10) were 0.10, 0.25, 0.18 and 0.30 μg·kg⁻¹, respectively. The recoveries of aflatoxins in samples were 90.1%-104.4% and RSDs were <4.4%. The developed method was further applied to the determination of aflatoxins in peanut, vegetable oil and tea samples, and the results indicated that peanut (26.9%), vegetable oils (28.0%) and tea (5.3%) samples were contaminated with aflatoxins, with levels ranging from 0.49 to 20.79 μg·kg⁻¹.

Silica aerogel, a kind of nanoporous material, is regarded as a desired drug carrier for its low toxicity, high specific surface area, and excellent biocompatibility. Using silica aerogel in a drug carrier may be an appropriate method to improve the performance of pure resveratrol. In this study, resveratrol-loaded silica aerogel (RSA) as a drug delivery system was prepared by the sol-gel method. Before gelling, resveratrol was added into the hydrolyzed tetraethyl orthosilicate (TEOS) ethanol solution then dispersed by stir and ultrasound. The results showed that RSA has a high loading rate of 19% with low cost and excellent biocompatibility. The SEM images showed that silica aerogel wraps up outside the resveratrol. Sustained releasing effect could be observed in RSA after 1 h, while pure resveratrol did not display this. The release of RSA lasted for over 6 h, and the release amount reached over 90% and 80% in either simulated gastric fluid (pH = 2.0) or phosphate-buffered saline (pH = 7.4) at 37 °C. Preliminary in vitro toxicity test revealed RSA to be biocompatible and stable; and when coupled with the anti-inflammatory effects of resveratrol, showed good potential for osteoarthritis treatment.

IntroductionIntravaginal products, including silicon dioxide-based gels, are marketed to support short-term high-risk human papillomavirus (hrHPV) clearance or loss of detectability, but independent randomized evidence testing these short-term claims against observation is limited. We evaluated whether daily intravaginal silicon dioxide-based gel treatment increases the proportion of women with no detectable cervical hrHPV DNA compared with observation alone.Material and methodsThis prospective, single-center, parallel-group, randomized, open-label controlled trial included women with PCR-confirmed cervical hrHPV infection and no indication for immediate treatment. Participants were randomized 1:1 to 3 months of self-administered daily intravaginal gel treatment or observation alone. The primary outcome was absence of detectable cervical hrHPV DNA by PCR at 3 months. Secondary outcomes during the randomized study period were patient-reported satisfaction and adverse events.Trial registrationClinicalTrials.gov, NCT05509413, https://clinicaltrials.gov/study/NCT05509413.ResultsBetween November 2022 and January 2025, 242 women were randomized, with 121 allocated to each group. Primary-endpoint data were available for 208 women. At 3 months, hrHPV DNA was not detected in 18/99 women (18%) in the gel treatment group and 23/109 women (21%) in the observation group (absolute risk difference -2.9 percentage points, 95% CI -14 to 8; p = 0.60). A reduced post hoc adjusted sensitivity analysis did not materially change the interpretation of the primary comparison. Patient-reported adverse events were more frequent in the gel treatment group than in the observation group (32/99 [32%] vs. 2/106 [2%]; absolute risk difference 30 percentage points, 95% CI 21 to 40; p ConclusionsIn this randomized trial, 3 months of daily intravaginal silicon dioxide-based gel treatment did not improve short-term loss of detectable cervical hrHPV DNA compared with observation alone. The trial did not reproduce the large short-term virologic benefit suggested by prior product-related studies. The findings do not support routine use of this intervention solely to promote short-term hrHPV non-detectability in women without an indication for immediate treatment, particularly given the higher frequency of local adverse events.