A review of aptamer-conjugated nanomaterials for analytical sample preparation: Classification according to the utilized nanomaterials

BACKGROUND

Sample extraction before detection is a critical step in analysis. Since targets of interest are often found in complex matrices, the sample can not be directly introduced to the analytical instrument. Nanomaterials with unique physical-chemical properties are excellent supports for use in sorbent-based extraction. However, they lack selectivity and thus need to be functionalized with target-capturing molecules. Antibodies and molecularly imprinted polymers (MIPs) can be used for this purpose, but they have some problems that limit their practical applications. Hence, functionalization of nanomaterials for selectivity remains a problem.

RESULTS

Nucleic acid aptamers are affinity reagents that can provide superiority to antibodies since they can be selected in vitro and at a lower cost. Moreover, aptamers can be chemically synthesized and easily modified with different functional groups. Hence, aptamers are good candidates to impart selectivity to the nanomaterials. Recent studies focus on the integration of aptamers with magnetic nanoparticles, carbon-based nanomaterials, metal-organic frameworks, gold nanoparticles, gold nanorods, silica nanomaterials, and nanofibers. The unique properties of nanomaterials and aptamers make the aptamer-conjugated nanomaterials attractive for use in sample preparation. Aptamer-functionalized nanomaterials have been successfully used for selective extraction of proteins, small molecules, and cells from different types of complex samples such as serum, urine, and milk. In particular, magnetic nanoparticles have a wider use due to the rapid extraction of the sample under magnetic field.

SIGNIFICANCE

In this review, we aim to emphasize how beneficial features of nanomaterials and aptamers could be combined for extraction or enrichment of the analytes from complex samples. We aim to highlight that the benefits are twofold in terms of selectivity and efficiency when employing nanomaterials and aptamers together as a single platform.

Deacetylation of Histones and Non-histone Proteins in Inflammatory Diseases and Cancer Therapeutic Potential of Histone Deacetylase Inhibitors

Epigenetic changes play an important role in the pathophysiology of autoimmune diseases such as allergic asthma, multiple sclerosis, lung diseases, diabetes, cystic fibrosis, atherosclerosis, rheumatoid arthritis, and COVID-19. There are three main classes of epigenetic alterations: post-translational modifications of histone proteins, control by non-coding RNA and DNA methylation. Since histone modifications can directly affect chromatin structure and accessibility, they can regulate gene expression levels. Abnormal expression and activity of histone deacetylases (HDACs) have been reported in immune mediated diseases. Increased acetylated levels of lysine residues have been suggested to be related to the overexpression of inflammatory genes. This review focuses on the effect of HDAC modifications on histone and non-histone proteins in autoimmune diseases. Furthermore, we discuss the potential therapeutic effect of HDAC inhibitors (HDACi) used in these diseases.

Congenital infections in Hong Kong: beyond TORCH

Congenital infections refer to a group of perinatal infections that are caused by pathogens transmitted from mother to child during pregnancy (transplacentally) or delivery (peripartum) which may have similar clinical presentations, including rash and ocular findings. TORCH is the acronym that covers these infections (toxoplasmosis, other [syphilis], rubella, cytomegalovirus, herpes simplex virus). Other important causes of intrauterine/perinatal infection include human immunodeficiency virus, varicella-zoster virus, Treponema pallidum, Zika virus, and parvovirus B19. This overview aims to describe various congenital infections beyond TORCH with a Hong Kong perspective. Intrauterine and perinatal infections are a major cause of in utero death and neonatal mortality, and an important contributor to childhood morbidity. A high index of suspicion for congenital infections and awareness of the prominent features of the most common congenital infections can help to facilitate early diagnosis, tailor appropriate diagnostic evaluation, and initiate appropriate early treatment. Intrauterine infections should be suspected in newborns with clinical features including microcephaly, seizures, cataract, hearing loss, congenital heart disease, hepatosplenomegaly, small for gestational age, and/or rash. Primary prevention of maternal infections during pregnancy is key to the prevention of congenital infection, and resources (if available) should focus on public health promotion and pre-marital counselling.

Congenital infections in Hong Kong: an overview of TORCH

Congenital infections refer to a group of perinatal infections that may have similar clinical presentations, including rash and ocular findings. TORCH is the acronym that covers these infections (toxoplasmosis, other [syphilis], rubella, cytomegalovirus, herpes simplex virus). There are, however, other important causes of intrauterine/perinatal infections, including enteroviruses, varicella zoster virus, Zika virus, and parvovirus B19. Intrauterine and perinatal infections are significant causes of fetal and neonatal mortality and important contributors to childhood morbidity. A high index of suspicion for congenital infections and awareness of the prominent features of the most common congenital infections can help to facilitate early diagnosis, tailor appropriate diagnostic evaluation, and if appropriate, initiate early treatments. In the absence of maternal laboratory results diagnostic of intrauterine infections, congenital infections should be suspected in newborns with certain clinical features or combinations of clinical features, including hydrops fetalis, microcephaly, seizures, cataract, hearing loss, congenital heart disease, hepatosplenomegaly, jaundice, or rash. Primary prevention of maternal infections during pregnancy is the cornerstone of prevention of congenital infection. Available resources should focus on the promotion of public health.