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Effective oral drugs and vaccines require high delivery efficiency across the gastrointestinal epithelia and protection of medically effective payloads (i.e., immunogens) against gastric damage. In this study, hollowed nanocarriers (NCs: silica nanospheres and gold nanocages) with poly-l-lysine (PLL) coating and mammalian orthoreovirus cell attachment protein σ1 functionalization (NC-PLL-σ1) were explored as functional oral drug delivery vehicles (ODDVs). The transport of these ODDVs to mucosal lymphoid tissues could be facilitated by microfold cells (M-cells) mediated transcytosis (via σ1-α2–3-linked sialic acids adherence) across gastrointestinal epithelia. PLL coating provided protection and slow-release of rhodamine 6 G (R6G), a model payload. The transport effectiveness of these ODDVs was tested on intestinal organoid monolayers in vitro. When compared with other experimental groups, the fully functionalized ODDV system (with PLL-σ1) demonstrated two significant advantages: a significantly higher transport efficiency (198% over blank control at 48 h); and protection of payloads which led to both better transport efficiency and extended-release of payloads (61% over uncoated carriers at 48 h). In addition, it was shown that the M cell presence in intestinal organoid monolayers (modulated by Rank L stimulation) was a determining factor on the transport efficiency of the ODDVs: more M-cells (induced by higher Rank L) in the organoid monolayers led to higher transport efficiency for ODDV-delivered model payload (R6G). The fully functionalized ODDVs showed great potential as effective oral delivery vehicles for drugs and vaccines.

Silver Carp (SC) is an under-utilized, invasive species in North American river systems. In this study, the synergistic effects of manufactured Microfiber (MMF), Transglutaminase (TG), and chicken skin collagen (CLG)) to enhance surimi gel quality from frozen SC were studied. The gel strength, textural properties, rheological properties, water-holding capacity (WHC), water mobility, microstructure, and protein composition of the gel samples were determined to assess the impact of the additives individually and synergistically. The results suggested that TG had the most pronounced effect on the surimi gel properties by promoting protein cross-linking. Synergistic effects between TG, MMF, and CLG can bring effective gel property enhancement larger than the individual effect of each additive alone. With the established response-surface models, the combination of CLG and MMF can be optimized to produce surimi gels with less TG but comparable in properties to that of the optimal result with high TG usage. The findings of this study provided a technical foundation for making high-quality surimi gel products out of frozen-stored SC with synergistic utilization of additives, which could serve as guidelines for the industrial development of new surimi products.

For potato production, continuous cropping (CC) could lead to autotoxicity buildup and microflora imbalance in the field soil, which may result in failure of crops and reduction in yield. In this study, non-targeted metabolomics (via liquid chromatography with tandem mass spectrometry (LC–MS/MS)) combined with metagenomic profiling (via high-throughput amplicon sequencing) were used to evaluate correlations between metabolomics of potato root exudates and communities of bacteria and fungi around potato plants to illustrate the impacts of CC. Potato plants were grown in soil collected from fields with various CC years (0, 1, 4, and 7 years). Metabolomic analysis showed that the contents and types of potential autotoxins in potato root exudates increased significantly in CC4 and CC7 plants (i.e., grown in soils with 4 and 7 years of CC). The differentially expressed metabolites were mainly produced via alpha-linolenic acid metabolism in plant groups CC0 and CC1 (i.e., no CC or 1 year CC). The metabolomics of the groups CC4 and CC7 became dominated by styrene degradation, biosynthesis of siderophore group non-ribosomal peptides, phenylpropanoid biosynthesis, and biosynthesis of various plant secondary metabolites. Continuous cropping beyond 4 years significantly changed the bacterial and fungal communities in the soil around the potato crops, with significant reduction of beneficial bacteria and accumulation of harmful fungi. Correlations between DEMs and microflora biomarkers were established with strong significances. These results suggested that continuous cropping of potato crops changed their metabolism as reflected in the plant root exudates and drove rhizosphere microflora to directions less favorable to plant growth, and it needs to be well managed to assure potato yield.

//Nbss and α-Nb5Si3 phases were detected. Meanwhile, Nb2C was observed, and the crystal forms of Nb5Si3 changed in the C-doped composites. Furthermore, micron-sized and nano-sized Nb2C particles were found in the Nbss layer. The orientation relationship of Nb2C phase and the surrounding Nbss was [001]Nbss//[010]Nb2C, (200) Nbss//(101) Nb2C. Additionally, with the addition of C, the compressive strength of the composites, at 1400 °C, and the fracture toughness increased from 310 MPa and 11.9 MPa·m1/2 to 330 MPa and 14.2 MPa·m1/2, respectively; the addition of C mainly resulted in solid solution strengthening.

In this review, we aim to provide a summary of recent research advancements and applications of algin (i.e., alginic acid) and alginate-hybrid materials (AHMs) in medical fields. Algin/alginate are abundant natural products that are chemically inert and biocompatible, and they have superior gelation properties, good mechanical strengths, and biodegradability. The AHMs have been widely applied in wound dressing, cell culture, tissue engineering, and drug delivery. However, medical applications in different fields require different properties in the AHMs. The drug delivery application requires AHMs to provide optimal drug loading, controlled and targeted drug-releasing, and/or visually guided drug delivery. AHMs for wound dressing application need to have improved mechanical properties, hydrophilicity, cell adhesion, and antibacterial properties. AHMs for tissue engineering need improved mechanical properties that match the target organs, superior cell affinity, and cell loading capacity. Various methods to produce AHMs that meet different needs were summarized. Formulations to form AHMs with improved stability, drug/cell-loading capacity, cell adhesion, and mechanical properties are active research areas. This review serves as a road map to provide insights into the strategies to develop AHMs in medical applications.

In order to improve the gel quality of silver carp (Hypophthalmichthys molitrix) surimi, the texture and rheological properties and microstructure of silver carp surimi gel products were analyzed by adding Laminaria japonica (LJ), Undaria pinnatifida (UP) and Sargassum fusiforme (SF) slurries. After adding kelp slurry (KS), the gel strength reached the highest level of 1047.26 ± 85.04 (g·mm). The carbonyl content and surface hydrophobicity of surimi protein increased, while the free amino groups, total sulfhydryl groups, and fluorescence intensity decreased significantly. The results of transform infrared spectroscopy (FT-IR), circular dichroic (CD), and Raman spectra showed that the KS promoted the change of the secondary structure of protein. Scanning electron microscopy (SEM) images revealed that kelp slurry had a more compact gel microstructure. In conclusion, the kelp slurry could significantly increase the gel strength, improve the quality of surimi products, enrich the nutrition of silver carp surimi, and have great significance for expanding the application range of seaweed.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by accumulation of misfolded α-synuclein within the central nervous system (CNS). Visual problems in PD patients are common, although retinal pathology associated with PD is not well understood. The purpose of this study was to investigate retinal pathology in a transgenic mouse model (TgM83) expressing the human A53T α-synuclein mutation and assess the effect of α-synuclein “seeding” on the development of retinal pathology. Two-month-old TgM83 mice were intracerebrally inoculated with brain homogenate from old (12–18 months) TgM83 mice. Retinas were then analyzed at 5 months of age. We analyzed retinas from 5-month-old and 8-month-old uninoculated healthy TgM83 mice, and old (12–18 months) mice that were euthanized following the development of clinical signs. Retinas of B6C3H mice (genetic background of the TgM83 mouse) served as control. We used immunohistochemistry and western blot analysis to detect accumulation of α-synuclein, pTauThr231, inflammation, changes in macroautophagy, and cell death. Raman spectroscopy was used to test the potential to differentiate between retinal tissues of healthy mice and diseased mice. This work demonstrates retinal changes associated with the A53T mutation. Retinas of non-inoculated TgM83 mice had accumulation of α-synuclein, “pre-tangle” tau, activation of retinal glial cells, and photoreceptor cell loss by 8 months of age. The development of these changes is accelerated by inoculation with brain homogenate from clinically ill TgM83 mice. Compared to non-inoculated 5-month-old TgM83 mice, retinas of inoculated 5-month-old mice had increased accumulation of α-synuclein (pSer129) and pTauThr231 proteins, upregulated microglial activation, and dysregulated macroautophagy. Raman spectroscopic analysis was able to discriminate between healthy and diseased mice. This study describes retinal pathology resulting from the A53T mutation. We show that seeding with brain homogenates from old TgM83 mice accelerates retinal pathology. We demonstrate that Raman spectroscopy can be used to accurately identify a diseased retina based on its biochemical profile, and that α-synuclein accumulation may contribute to accumulation of pTauThr231 proteins, neuroinflammation, metabolic dysregulation, and photoreceptor cell death. Our work provides insight into retinal changes associated with Parkinson's disease, and may contribute to a better understanding of visual symptoms experienced by patients.

Postmortem characteristics of Patinopecten yessoensis adductor muscle (PYAM) were evaluated by biochemical, chemical and textural changes during iced storage for 14 days. Triphosphate (ATP) and its breakdown products, K-value, total volatile basic nitrogen (TVB-N), pH, water-holding capacity (WHC), color, texture, protein degradation and cathepsin activities were monitored. K-value increased linearly from 5.9 ± 0.9% at day 0 to 28.1 ± 2.4% at day 2 and 70.2 ± 1.8% at day 12. Spoilage indicator TVB-N (mg/100 g) increased from 10.0 ± 0.6 to 34.6 ± 3.1 at day 12. Textural parameters (e.g., hardness, chewiness, springiness, adhesiveness, and shear force) followed a declining trend over the storage. The WHC decreased from 85.1 ± 3.1% at day 0 to 70.5 ± 1.8% at day 12. SDS-PAGE result indicated that proteolysis occurred in actin and myosin heavy chain (MHC) at day 14. Both cathepsin B and L increased throughout the iced storage, peaking at 1.47-fold and 1.08-fold, respectively, suggesting that cathepsin B and L played important roles in the deterioration of PYAM quality. The overall results indicated that PYAM was suitable to be consumed raw within the first 2 days, and to be processed in no more than 11 days.

The primary plant cell wall is a complex matrix composed of interconnected polysaccharides including cellulose, hemicellulose, and pectin. Changes of this dynamic polysaccharide system play a critical role during plant cell development and differentiation. A better understanding of cell wall architectures can provide insight into the plant cell development. In this study, a Raman spectroscopic imaging approach was developed to visualize the distribution of plant cell wall polysaccharides. In this approach, Surface-enhanced Raman scattering (SERS through self-assembled silver nanoparticles) was combined with Raman labels (4-Aminothiophenol. 4ATP) and targeted enzymatic hydrolysis to improve the sensitivity, specificity, and throughput of the Raman imaging technique, and to reveal the distribution of pectin and its co-localization with xyloglucan inside onion epidermal cell (OEC) wall. This technique significantly decreased the required spectral acquisition time. The resulted Raman spectra showed a high Raman signal. The resulted Raman images successfully revealed and characterized the pectin distribution and its co-localization pattern with xyloglucan in OEC wall.

It is difficult to maintain the high quality of sea cucumber Stichopus japonicus (S. japonicus) during regular thermal processing due to the special physiochemical makeup of S. japonicus body wall (SJBW) that affects its textural properties. Hence, it is very necessary to understand the parameters controlled textural alteration and the potential mechanisms during thermal processing of SJBW. In the present study, morphology, hardness and chewiness of SJBW gradually changed starting from 3 h during thermal processing. SDS-PAGE analysis indicated that notable proteolysis occurred in actin and other proteins with molecular weight of 200 kDa in a time-dependent manner. DNA fragmentation, cathepsin L and caspase-3-like activities also increased in SJBW. Within 1 h of incubation, both phosphorylated p38 and c-jun N-terminal kinase (JNK) and reactive oxygen species (ROS) production in SJBW reached the highest levels, and then returned back to the original levels after 3 h. A plausible signaling pathway in SJBW during low-temperature treatment is as follows: ROS produced, Mitogen-activated protein kinases (MAPK) phosphorylation, endogenous enzyme activation, DNA damage, protein degradation, and textural tenderization. Understanding the molecular mechanism underlying physiochemical changes during low-temperature treatment would be essential to achieve better control of the texture and quality of SJBW.

Undaria pinnatifida (UP) is a brown algae commonly consumed as food in Asian countries. The purpose of this study was to compare the effects of different domestic cooking methods (i.e., air frying (AF), microwaving, and high temperature and pressure (HTP) cooking) on the nutritional and bioactive substances in UP, as well as on UP color and texture, in order to identify methods to retain beneficial components better. In this study, microwave treatment resulted in better retention of color, polysaccharide (4.17 ± 0.07 mg glucose equivalents (GE)/g dry weight (dw) ), total phenol content (TPC) (1.50 ± 0.0062 mg gallic acid equivalents (GAE)/g dw) as well as chlorophyll a (18.18 ± 0.41 mg/g fresh weight (fw) ) and fucoxanthin (281.78 ± 17.06 μg/g dw). HTP treatment increased the TPC of UP (1.69 ± 0.0075 mg GAE/g dw), and AF treatment resulted in a lower loss of total amino acids (2.14 ± 0.15%). Overall, microwave cooking appeared to be the best among the three in producing cooked UP with high quality. This study provided a useful guideline in selection of cooking for UP which could retain more health-beneficial substances and yield products with better eating qualities to improve human diet.

This review aims to provide an informative summary of studies on extraction and nanoencapsulation of phlorotannins to improve their bioavailability and bioactivity. The origin, structure, and different types of phlorotannins were briefly discussed, and the extraction/purification/characterization methods for phlorotannins were reviewed, with a focus on techniques to improve the bioactivities and bioavailability of phlorotannins via nano-sized delivery systems. Phlorotannins are promising natural polyphenol compounds that have displayed high bioactivities in several areas: anticancer, anti-inflammation, anti-HIV, antidiabetic, and antioxidant. This review aims to provide a useful reference for researchers working on developing better utilization strategies for phlorotannins as pharmaceuticals, therapeuticals, and functional food supplements.

Background: Sea cucumber is a seafood of high nutritional value. During its processing, sea cucumber processing liquor is routinely produced, which is usually discarded as waste. The chemical composition of this processing liquor is similar to sea cucumbers themselves. Hence, valuable ingredients, such as functional polysaccharides, could be obtained from them. Results: Biologically active polysaccharides from sea cucumber processing liquor were extracted through protease hydrolysis and electroosmosis. The analysis revealed that the polysaccharide extract from sea cucumber processing liquor (PESCPL) is predominantly composed of mannose, in addition to some glucose and fucose. The antioxidant activity of PESCPL was analyzed using in vitro. It was demonstrated that PESCPL could effectively scavenge 1,1-diphenyl-2-picrylhydrazyl radicals, hydroxyl radicals, and superoxide anion radicals. The effect of PESCPL was investigated in vivo by using mice model fed with high-fat diets with/without PESCPL supplement. It was shown that PESCPL could increase the catalase and superoxide dismutase activity in the serum and decrease serum malonaldehyde content. Furthermore, mice fed with PESCPL diet showed a considerable decrease in the serum cholesterol and triglyceride levels and an increase in high-density lipoprotein cholesterol levels. Conclusions: Our research highlights that PESCPL is a natural antioxidant and could be utilized as a therapeutic supplement for dyslipidemia.

Fucoxanthin (FX), a natural carotenoid found in seaweed with multiple functional activities, is unstable with a poor water solubility that limits its utilization. This study aimed to improve FX’s stability and bioavailability via the nano-encapsulation of FX in polyvinylpyrrolidone (PVP)-coated FX@PVP nanoparticles (NPs). The FX@PVP NPs were evaluated in terms of their morphology, stability, encapsulation efficiency (EE), loading capacity (LC), and in vitro release to optimize the encapsulation parameters, and a 1:8 FX:PVP ratio was found to perform the best with the highest EE (85.50 ± 0.19%) and LC (10.68 ± 0.15%) and improved FX stability. In addition, the FX@PVP NPs were shown to effectively deliver FX into Caco-2 cancer cells, and the accumulation of FX in these cancer cells showed pro-oxidative activities to ameliorate H2O2-induced damage and cell death. The FX@PVP NPs could potentially become a new therapeutical approach for targeted cancer treatment.

Profiling of polyphenolics in four types of brown macroalgae, namely Laminaria japonica (L. japonica), Undaria pinnatifida (U. pinnatifida), Sargassum fusiforme (S. fusiforme), and Ascophyllum nodosum (A. nodosum), and their effect on oxidation resistance were investigated for the first time. Polyphenolic extracts from marine brown macroalgae were shown to effectively remove oxidants from cells and cellular systems. A. nodosum showed the highest antioxidant activity among evaluated brown macroalgae, showing a better scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and alleviating oxidative damage caused by hydrogen peroxide to human keratinocytes (HaCaT) cells. Through Q-Exactive HF-X mass spectrometry analysis, 12 polyphenolic compounds were preliminarily identified, including phlorotannins, phenolic acids, and flavonoids. Significant differences in content and variety of polyphenolics were found in evaluated brown macroalgae, which could be related to differences in antioxidant activity in vivo and in vitro. Moreover, the antioxidant activity might be related to the total phenolic content and the types of polyphenolics, especially phlorotannins. The findings presented in this study indicate that A. nodosum could be used as an important substitute for functional ingredients in foods and pharmaceutical preparations, as well as a raw material for phlorotannins research.

Among the physical, chemical and biological hazards that could arise with respect to food safety, bacterial contamination has been one of the main concerns in recent years. Bacterial contamination in low moisture foods (LMFs) was an emerging threat which used to draw less attention as LMFs were considered at low risk of such a hazard. Bacteria can survive in low moisture environments and cause foodborne diseases once they enter the digestive system. Common detection methods such as ELISA and PCR are not well suited to LMFs, as most of them operate under aqueous environments. In this study, a Dual Immunological Raman-Enabled Crosschecking Test (DIRECT) was developed for LMFs using a nano-scaled surface enhanced Raman scattering (SERS) biosensor platform and multivariate discriminant analysis with a portable Raman spectrometer. It could provide a limit of detection (LOD) of 102 CFU/g of bacteria in model LMFs, with a detection time of 30–45 min. It has the potential to become a quick screening method for on-site bacteria detection for LMFs to identify food safety risks in real time.

Phlorotannins are a group of major polyphenol secondary metabolites found only in brown algae and are known for their bioactivities and multiple health benefits. However, they can be oxidized due to external factors and their bioavailability is low due to their low water solubility. In this study, the potential of utilizing nanoencapsulation with polyvinylpyrrolidone (PVP) to improve various activities of phlorotannins was explored. Phlorotannins encapsulated by PVP nanoparticles (PPNPS) with different loading ratios were prepared for characterization. Then, the PPNPS were evaluated for in vitro controlled release of phlorotannin, toxicity and antioxidant activities at the ratio of phlorotannin to PVP 1:8. The results indicated that the PPNPS showed a slow and sustained kinetic release of phlorotannin in simulated gastrointestinal fluids, they were non-toxic to HaCaT keratinocytes and they could reduce the generation of endogenous reactive oxygen species (ROS). Therefore, PPNPS have the potential to be a useful platform for the utilization of phlorotannin in both pharmaceutical and cosmetics industries.

A new sea urchin polysaccharide (SUP) was extracted from the gonad of sea urchin (Strongylocentrotus intermedius), and its bioactivity to synergistically enhance the functionality of bone morphogenetic protein-2 (BMP-2) induced osteoblastic differentiation was characterized. Results showed that the SUP is homogenous with an average molecular weight of 4.4 kDa, and it is mainly composed of mannose with a small number of glucose and N-acetylglucosamine, with a backbone of alternating 1, 4-D-Man and 1, 3-D-Man residues. The SUP was shown to synergistically enhance BMP-2 induced osteoblastic differentiation in C2C12 myoblast cells, evidenced by a significant increase in the activity of alkaline phosphatase (ALP), when the concentration of the SUP was higher than 10 µg/mL. The elevated ALP activity was also confirmed by histochemical staining of C2C12 myoblast cells. These results suggest that the SUP can promote bone regeneration and may serve as a functional food supplement for bone health.

Undaria pinnatifida sporophyll (U. pinnatifida) is a major byproduct of U. pinnatifida (a brown algae) processing. Its phenolic constituents, phlorotannins, are of special interest due to their intrinsic ability to precipitate proteins. Herein, a high-temperature extraction procedure was used to isolate these biologically active compounds. The heating temperature, heating time, and extraction solvent (ethanol) concentration were examined with response surface analysis to determine the optimal conditions to achieve the maximum extraction rate. The analysis revealed the optimal conditions to be: 170 °C of heating temperature, 5.2 h of heating time, and 52% ethanol concentration for a yield of 10.7 ± 0.2 mg gallic acid equivalent/g dry weight (GAE/g DW) of sample. Compared to epigallocatechin gallate (EGCG), the extracted phlorotannins displayed higher antioxidant activity on H2O2-induced RAW 264.7 cells with improved efficiency. Furthermore, the compounds exhibited strong anti-inflammatory activity. These findings potentially can be utilized to guide development of novel functional foods and food supplements from sea-originated resources such as brown algae.

In this study, three synthetic zinc-chelating peptides (ZCPs) derived from sea cucumber hydrolysates with limited or none of the common metal-chelating amino-acid residues were analyzed by flame atomic absorption spectroscopy, circular dichroism spectroscopy, size exclusion chromatography, zeta-potential, Fourier transform infrared spectroscopy, Raman spectroscopy and nuclear magnetic resonance spectroscopy. The amount of zinc bound to the ZCPs reached maximum values with ZCP:zinc at 1:1, and it was not further increased by additional zinc presence. The secondary structures of ZCPs were slightly altered, whereas no formation of multimers was observed. Furthermore, zinc increased the zeta-potential value by neutralizing the negatively charged residues. Only free carboxyl in C-terminus of ZCPs was identified as the primary binding site of zinc. These results provide the theoretical foundation to understand the mechanism of zinc chelation by peptides.

Anisotropic nanoparticles (i.e., silver nanocubes) were functionalized with target-specific antibodies and Raman active tags to serve as nanoprobes for the rapid detection of bacteria in a test-in-a-tube platform. A self-referencing scheme was developed and implemented in which surface enhanced Raman spectroscopic (SERS) signatures of the targets were observed superimposed with the SERS signals of the Raman tags. The assessment through the dual signals (superimposed target and tag Raman signatures) supported a specific recognition of the targets in a single step with no washing/separation needed to a sensitivity of 102 CFU/mL, even in the presence of non-target bacteria at a 10 times higher concentration. The self-referencing protocol implemented with a portable Raman spectrometer potentially can become an easy-to-use, field-deployable spectroscopic sensor for onsite detection of pathogenic microorganisms.

Background: With the rapid ageing of the population, injuries are increasingly threatening the health of elderly individuals. A comprehensive evaluation of the injury burden is important for selecting and formulating strategies for injury prevention. Objective: To evaluate the temporal trends of injury burden among elderly Chinese individuals aged 60 years and older. Methods: Based on the results of the Global Burden of Disease Study 2019, the injury mortality, morbidity, and disability-adjusted life years (DALYs) of elderly individuals from 1990 to 2019 were estimated by age and sex. The autoregressive integrated moving average model was used to predict the injury burden in the next decade. Results: In 2019, there were an estimated 304 373 deaths due to injuries in China, accounting for 3.55 % of all deaths. The main cause of injury-related death was unintentional injuries (67.28 deaths per 100 000), followed by transport injuries (30.44 deaths per 100 000). The standardized DALYs rate due to injuries among elderly individuals was 3488.54 DALYs per 100 000. In the past 30 years, the morbidity of injuries among elderly individuals in China has increased by 52.18 %. In 2030, we estimated that there will be 398 200 deaths of elderly individuals due to injury. Conclusions: Over 21% of injury-related deaths among elderly individuals occurred in China. The injury burden among elderly individuals is high, and efforts are needed to inform injury prevention policies and adopt injury prevention strategies to reduce the injury burden and promote the health and well-being of elderly individuals.

Background: It is challenging to achieve ultrasensitive and selective detection of waterborne pathogens at extremely low levels (i.e., single cell/mL) using conventional methods. Even with molecular methods such as ELISA or PCR, multi-enrichment steps are needed which are labor and cost intensive. In this study, we incorporated nano-dielectrophoretic microfluidic device with Surface enhanced Raman scattering (SERS) technique to build a novel portable biosensor for easy detection and characterization of Escherichia coli O157:H7 at high sensitivity level (single cell/mL). Results: A multiplexing dual recognition SERS scheme was developed to achieve one-step target detection without the need to separate target-bound probes from unbound ones. With three different SERS-tagged molecular probes targeting different epitopes of the same pathogen being deployed simultaneously, detection of pathogen targets was achieved at single cell level with sub-species specificity that has not been reported before in single-step pathogen detection. Conclusion: The self-referencing protocol implements with a Nano-dielectrophoretic microfluidic device potentially can become an easy-to-use, field-deployable spectroscopic sensor for onsite detection of pathogenic microorganisms. [ABSTRACT FROM AUTHOR]

Anisotropic nanoparticles (i.e., silver nanocubes) were functionalized with target-specific antibodies and Raman active tags to serve as nanoprobes for the rapid detection of bacteria in a test-in-a-tube platform. A self-referencing scheme was developed and implemented in which surface enhanced Raman spectroscopic (SERS) signatures of the targets were observed superimposed with the SERS signals of the Raman tags. The assessment through the dual signals (superimposed target and tag Raman signatures) supported a specific recognition of the targets in a single step with no washing/separation needed to a sensitivity of 10² CFU/mL, even in the presence of non-target bacteria at a 10 times higher concentration. The self-referencing protocol implemented with a portable Raman spectrometer potentially can become an easy-to-use, field-deployable spectroscopic sensor for onsite detection of pathogenic microorganisms. [ABSTRACT FROM AUTHOR]

Early detection of pathological changes and progression in glaucoma and other neuroretinal diseases remains a great challenge and is critical to reduce permanent structural and functional retina and optic nerve damage. Raman spectroscopy is a sensitive technique that provides rapid biochemical characterization of tissues in a nondestructive and noninvasive fashion. In this study, spectroscopic analysis was conducted on the retinal tissues of seven beagles with acute elevation of intraocular pressure (AEIOP), six beagles with compressive optic neuropathy (CON), and five healthy beagles. Spectroscopic markers were identified associated with the different neuropathic conditions. Furthermore, the Raman spectra were subjected to multivariate discriminate analysis to classify independent tissue samples into diseased/healthy categories. The multivariate discriminant model yielded an average optimal classification accuracy of 72.6% for AEIOP and 63.4% for CON with 20 principal components being used that accounted for 87% of the total variance in the data set. A strong correlation (R² > 0.92) was observed between pattern electroretinography characteristics of AEIOP dogs and Raman separation distance that measures the separation of spectra of diseased tissues from normal tissues; however, the underlining mechanism of this correlation remains to be understood. Since AEIOP mimics the pathological symptoms of acute/early-stage glaucoma, it was demonstrated that Raman spectroscopic screening has the potential to become a powerful tool for the detection and characterization of early-stage disease. [ABSTRACT FROM AUTHOR]

Rapid and accurate evaluation of pollutant contamination in water is one of the key tasks of environmental monitoring. To make onsite assessment feasible, the analytical tools should be easy to operate, with minimal sample preparation needs. Gold nanoparticle (AuNP)-based sensors have the potential to detect toxins, heavy metals, and inorganic and organic pollutants in water rapidly with high sensitivity, and they are expected to play an increasingly important role in environmental monitoring. In this article, the synthesis, fabrication and functionalization of AuNPs are discussed, and the recent advances in the development and application of AuNP-based sensors for the determination of various pollutants contamination in water are reviewed. [ABSTRACT FROM AUTHOR]

A novel colorimetric nitrite ion sensor was developed utilizing 4-aminothiophenol (4-ATP) modified gold nanorods (GNR). in the presence of nitrite ions, the deamination reaction was induced by heating the 4-ATP modified GNR in ethanol solution, resulting in the reduction of the GNR surface charges, which led to aggregation of GNRs and a colorimetric response that was quantitatively correlated to the concentration of nitrite ions. This simple assay was rapid (⩽10 min) and highly sensitive (<1 ppm of nitrite), and it can be used for rapid monitoring of drinking water quality. [ABSTRACT FROM AUTHOR]

Nonfluorescent labels were used for an array-format multiplex detection of alternative splice junctions of breast cancer susceptibility gene 1 (BRCA1) by surface-enhanced Raman scattering (SERS). A four-plex detection scheme using nonfluorescent labels was demonstrated for DNA sequences specific to four BRCA1 alternative splice variants: Δ(11q) (the last 3309 nt deleted from exon 11), Δ(9, 10) (exon 9 and 10 deleted), Δ(5) (exon 5 deleted), and Δ(5q, 6) (the last 22 nt of exon 5 and the entire exon 6 is deleted). This is the first proof-of-concept study to apply SERS-based detection using nonfluorescent labels to investigate alternative gene splicing. Detection sensitivity of up to 1 fM was demonstrated for the Raman labels chosen to clearly discriminate the splice junctions via specific target identification. The proposed approach has the potential to become a highly sensitive and selective tool for comprehensive alternative splicing profiling of BRCA1 or other genes relevant to specific diseases. [ABSTRACT FROM AUTHOR]

A chemical procedure to replace the cetyltrimethylammonium bromide (CTAB) cap on gold nanorods (GNRs) fabricated through seed-mediated growth with organothiol compounds 3-animo-5-mercapto-1,2,4-triazole (AMTAZ) and 11-mercaptoundecaonic acid (MUDA) was developed to reduce the cytotoxity of GNRs and facilitate further biofunctionalization. Compared to phosphatidylcholine (PC) modification, our procedure yields stable GNRs that are biocompatible and suitable for whole-cell studies. The PC-, AMTAZ-, and MUDA-activated GNRs all showed low cytotoxicity. By choosing different organothiols, net positive or negative charges could be created on the nanorod surface, for different applications. Gold nanorod molecular probes (GNrMPs) were fabricated by subsequent attachment of antibodies to the activated GNRs and were used to visualize and detect cell surface biomarkers in normal and transformed human breast epithelial cells, demonstrating the potential of developing novel biosensors using gold nanorods. The sensitivity of GNrMPs made from organothiol-activated GNRs is considerably higher than that of CTAB/PC-activated GNRs, demonstrating that the protocol reported here is favored in developing molecular probes using GNRs. [ABSTRACT FROM AUTHOR]

Gold nanorod molecular probes (GNrMPs) were designed and fabricated for multiplex identification of cell surface markers in HBECs. Cells were probed directly using dark field microscopy integrated with a spectral imager for simultaneous detection of up to three surface markers. The immunophenotype composition of these cell lines indicative of their metastasis potential was assessed using the GNrMPs. The technique has the potential to become an important tool for diagnosis and prognosis of breast and other cancers. [ABSTRACT FROM AUTHOR]

Gold nanorods (GNRs) with different aspect ratios were fabricated through seed-mediated growth and surface activation by alkanethiols for the attachment of antibodies to yield gold nanorod molecular probes (GNrMPs). Multiplex sensing was demonstrated by the distinct response of the plasmon spectra of the GNrMPs to binding events of three targets (goat anti-human IgG1 Fab, rabbit anti-mouse IgG1 Fab, rabbit anti-sheep IgG (H+L)). Plasmonic sensors are highly specific and sensitive and can be used to monitor refractive index changes caused by molecular interactions in their immediate vicinity with potential to achieve single-particle biosensing. This technique can play a key role in developing novel optical biosensors for both in vivo and in vitro detection and single-receptor kinetics. [ABSTRACT FROM AUTHOR]

Antibody (human IgG, anti-E. coli O157:H7, and anti-Salmonella) complexes on the surface of IR-transparent Ge-containing chalcogenide glass films were formed via thiol chemistry on 20-nm-thick gold islands. As a first step, the protocol was validated by monitoring fluorescently tagged targets to validate binding. FF-IR spectroscopy confirmed that the coating of the films with 20-nm gold did not have a significant effect on the propagation and penetration of IR evanescent waves through the film. The films functionalized with anti-E, coli O157:H7 and anti-Salmonella antibodies were used to detect E. coli O157:H7 and S. enteriditis through label-free IR fingerprinting. Highly selective detection of bacterial targets was achieved at both the species (E. coli vs. S. enteriditis) and strain level (E. coli O157:H7 vs E. coli K12). A mid-infrared approach could thus be used as a biosensor as well as a molecular fingerprinting tool. [ABSTRACT FROM AUTHOR]

With the rapid development of analytical techniques, it has become much easier to detect chemical and biological analytes, even at very low detection limits. In recent years, techniques based on vibrational spectroscopy, such as surface enhanced Raman spectroscopy (SERS), have been developed for non-destructive detection of pathogenic microorganisms. SERS is a highly sensitive analytical tool that can be used to characterize chemical and biological analytes interacting with SERS-active substrates. However, it has always been a challenge to obtain consistent and reproducible SERS spectroscopic results at complicated experimental conditions. Microfluidics, a tool for highly precise manipulation of small volume liquid samples, can be used to overcome the major drawbacks of SERS-based techniques. High reproducibility of SERS measurement could be obtained in continuous flow generated inside microfluidic devices. This article provides a thorough review of the principles, concepts and methods of SERS-microfluidic platforms, and the applications of such platforms in trace analysis of chemical and biological analytes. [ABSTRACT FROM AUTHOR]