Determination Of Cholesterol Research Articles

Porphyrin modified ZnCo2O4 nanospheres as the excellent peroxidase/oxidase dual nanozymes for colorimetric sensing of cholesterol

5,10,15,20-Tetrakis(4-carboxyl phenyl)porphyrin (H2TCPP) modified ZnCo2O4 nanospheres (H2TCPP-ZnCo2O4) were prepared by a two-step hydrothermal method. Compared with pure ZnCo2O4, H2TCPP-ZnCo2O4 possessed higher peroxidase-like activity and fast catalyze the chromogenic substrate 3,3,5,5-tetramethylbenzidine (TMB) into oxTMB by H2O2 with a blue change. The catalytic behaviors of H2TCPP-ZnCo2O4 is consistent with the Michaelis–Menten equation. Several techniques including electrochemical, fluorescent probes and capture agents were used to investigate the catalytic mechanism, which was identified as electron transfer and superoxide radical (•O2−), due to the synergetic effect between porphyrin molecules and ZnCo2O4. Based on the nanoperoxidase activity of H2TCPP-ZnCo2O4, a facile colorimetric sensing platforms was designed for the determination of H2O2 and cholesterol. The linear range for H2O2 determination is 100 to 200μM, with a detection limit of 76.297μM as well as cholesterol is 100 to 900μM, with a detection limit of 40.027μM

Innovative Peptide-Based Plasmonic Optical Biosensor for the Determination of Cholesterol.

Plasmonic-based biosensors have gained prominence as potent optical biosensing platforms in both scientific and medical research, attributable to their enhanced sensitivity and precision in detecting biomolecular and chemical interactions. However, the detection of low molecular weight analytes with high sensitivity and specificity remains a complex and unresolved issue, posing significant limitations for the advancement of clinical diagnostic tools and medical device technologies. Notably, abnormal cholesterol levels are a well-established indicator of various pathological conditions; yet, the quantitative detection of the free form of cholesterol is complicated by its small molecular size, pronounced hydrophobicity, and the necessity for mediator molecules to achieve efficient sensing. In the present study, a novel strategy for cholesterol quantification was developed, leveraging a plasmonic optical readout in conjunction with a highly specific cholesterol-binding peptide (C-pept) as a biorecognition element, anchored on a functionalized silica substrate. The resulting biosensor exhibited an exceptionally low detection limit of 21.95 µM and demonstrated a linear response in the 10-200 µM range. This peptide-integrated plasmonic sensor introduces a novel one-step competitive method for cholesterol quantification, positioning itself as a highly sensitive biosensing modality for implementation within the AVAC platform, which operates using reflective dark-field microscopy.

Non-enzymatic cholesterol biosensor: Electrochemical sensing based on peptide-polylactic acid thin film

Cholesterol is a fundamental lipid prevalent in eukaryotic cell membranes and circulating in the bloodstream bound to lipoproteins. It serves as a precursor to steroid hormones and is regarded as a biomarker for cardiovascular disease and other metabolic disorders. Numerous cholesterol detection methods predominantly rely on enzymes, which suffer from instability, leading to non-cost-effective biosensors with low sensitivity and poor reusability. Therefore, monitoring cholesterol levels with a feasible, rapid, and stable biosensor is critical for diagnosing and treating various disorders. This study aimed to develop a non-enzymatic cholesterol biosensor based on a selected cholesterol recognition peptide as the detection element. Screen-printed carbon electrodes (SPEs) modified with biocompatible poly-L-lactic acid (PLLA) porous nanomembranes (NMs) were utilized as support for the covalent immobilization of the peptide. Data obtained from electrochemical impedance spectroscopy (EIS) demonstrated the peptide's effective binding affinity towards cholesterol, paving the way for its implementation. The determination of cholesterol with the proposed biosensor exhibited a low limit of detection of 6.31 μM with linear responses ranging from 2–15 μM and 20–40 μM. These findings present an alternative method for cholesterol sensing by integrating novel peptides as biorecognition motifs with biocompatible polymeric materials, potentially useful as biocompatible and future point-of-care sensors.

A-224 Non HDL Cholesterol: could be e new cardiovascular disease risk stratification factor?

Abstract Background A worldwide study demonstrated that among all modifiable risk factors of Cardiovascular Disease (CVD) to the abnormal cholesterol levels is attributable the highest risk of events. LDL-C is considered the most important lipoprotein risk factor. Some recent epidemiologic studies have suggested that non-HDL cholesterol (N-HDL-C) may be superior to LDL-C for identifying CVD risk. N-HDL-C is easily calculated from a lipid profile and represents all apolipoprotein B containing lipoproteins. Recent guidelines recommend LDL-C as a primary indicator and non-HDL-C as secondary. Moreover, cholesterol ratios are useful to stratification; the TC/HDL-C is associated with morbidity and mortality in the general population; in addition, several studies have stated that high triglycerides (TG) levels and low HDL-C are associated with increased risk and could function as atherogenic index. Methods 11399 samples were analyzed on Atellica Solution for the determination of Total Cholesterol (TC), D-LDL-C, HDL-C and TG. In the absence of clinical parameters, based on the desirable levels recommended by the guidelines, CVD risk was evaluated by assigning a cut-off of 100 and 130 mg/dL for D-LDL-C and N-HDL-C respectively Results Patients cohort mean (±SD) for CT, D-LDL, HDL, TG and N-HDL-C are 180 mg/dL (±43.2), 113 mg/dL (± 38.5), 51.7 mg/dL (±15.6), 116 mg/dL (±73.8), 128 mg/dL (±39.5) respectively. Of the examined patients, the 57.7% were outpatients, 21.8% of infectious diseases and 12.6% of the cardiovascular department. Data about D-LDL-C and N-HDL-C comparison, evaluated on discordant patients, are shown in table 1. Conclusions The data obtained from evaluation would seem to confirm hypothesis according to which non-HDL cholesterol would have a greater power in the identification of CVD risk because of cholesterol ratios are suggestive of increased risk for patients with an LDL-C<100 and N-LDL-C>130 mg/dL. Further studies assessing CVD risk, not only through laboratory data, are necessary to confirm this supposition.

Total Cholesterol Determination Accuracy in Dried Blood Spots.

Background Detecting total cholesterol in dried blood spots could aid in identifying individuals with a high likelihood of familial hypercholesterolemia and could be used as a screening measure. This study aims to assess the diagnostic accuracy of dried blood spots on Whatman 903 paper cards using a manual enzymatic technique. Methods: A total of 394 samples were collected as serum and dried blood spots were compared. Cholesterol was determined in serum using the automated reference method, while cholesterol on paper was measured using a manual enzymatic method. Within- and between-day diagnostic variability were analyzed. The correlation between both methods was assessed using Passing-Bablok regression and Bland-Altman plot. Internal validation of our correlation formula was performed on 149 samples, along with external validation of the formula proposed by Corso et al. Results: The within- and between-day coefficient of variation was found to be lower than 10.14% and 14.09%, respectively. Passing-Bablok regression indicated a precision of 0.803 and an accuracy of 0.96. Internal validation precision was measured at 0.716. The resulting positive and negative predicted values were 0.77 and 0.92, respectively, vs. 0.46 and 0.96 from the external formula. Conclusions: Total cholesterol analysis in dried blood spots demonstrates high precision and reproducibility. This method reliably enables the incorporation of this biological marker into neonatal screening for familial hypercholesterolemia detection.

Determination of fatty acid, cholesterol, alpha-tocopherol, and aroma components of traditionally and commercially produced Trabzon butters

This study investigated 29 butter samples from Trabzon, Turkey. Cholesterol contents ranged from 134.13 to 325 mg/100 g, α-tocopherol contents ranged from 1.62 to 3.37 mg/100 g, and β-carotene contents ranged from 4.46 to 15.60 μg/g. Fatty acid composition analysis showed variations, with palmitic acid ranging from 26.11 % to 44.25 %, oleic acid from 19.55 % to 29.80 %, and linoleic acid from 1.63 % to 3.04 %. A total of 44 aroma components were identified. Traditional butter samples exhibited differences in aroma components and fatty acid composition compared to commercial butter. Notably, traditional butter had higher concentrations of octanoic and n-decanoic acids than commercial butter. Moreover, some aroma components such as N-butanoic acid 2-ethylhexyl ester, decanoic acid, and pentadecane were found exclusively in traditional butters. Traditional butter showed higher α-tocopherol and β-carotene contents. These findings underscore the distinct chemical profiles of traditional and commercial butter samples, influenced by production methods and possibly geographical origin.

Enhanced non-enzymatic multicomponent detection via one-step hydrothermal synthesis of widely dispersed Zn-SnO2 nanoparticles on nitrogen-doped reduced graphene oxide

ABSTRACT Herein, we report a new type of non-enzymatic nanostructured biosensor designed for the concurrent determination of dopamine, cholesterol, and glucose in human blood samples. The prepared biosensor using low-temperature one-pot hydrothermal processing is a Zn-doped SnO2-dispersed nitrogen-doped reduced graphene oxide (N-rGO)/Zn-SnO2 nanocomposite. This modified electrode allows direct electron transfer and thus offers electrochemical techniques to detect target molecules in analytes without the use of enzymes. The biosensor displayed good voltammetric responses within the human reference range: 20–70 nM for dopamine, 1–8 mM for cholesterol, and 1–10 mM for glucose. It also showed excellent reusability and can be restored by washing with ethanol. Due to the use of Zn-doped SnO2 nanoparticles for enhanced catalytic activity and N-rGO for high conductivity and active sites, sensitive and selective detection can be achieved. This hybrid composite demonstrates excellent catalytic activity, repeatability, stability, and clinical comparability for real-time measurement of dopamine, cholesterol, and glucose simultaneously.

INFLUENCE OF SEASON ON SERUM PROFILES OF SOME NUTRITIONAL METABOLITES DURING THE OESTRUS CYCLE IN SAVANNAH BROWN GOATS

The study was carried out to determine the effect of seasonal changes and oestrous cycle phase on serum levels of some nutritional metabolites in Savanna Brown (SB) goats. Twenty multiparous (n = 20) and cycling SB goats aged between 2-5 years (2-4 parity) and body mass index (BMI) of 20.17 ± 0.2 kg and 6.2±0.4 were used for the study. Ten animals were used per season. In each season, the animals were synchronized to the oestrus with a single injection of 7.5 mg PGF (Lutalyse). The animals were bled by jugular venipuncture for glucose, cholesterol and total protein determination of serum during the first oestrous cycle following treatment with PGF2. Blood sampling was done at d 0 and d 1 of the induced oestrus, twice weekly subsequently, and finally on d 0 and d lof the second estrus after PGF, treatment. The mean serum glucose concentration was higher (P < 0.05) in the cold-dry (4.3±0.1 mmol/L.) than in early rainy (3.8 ± 0.1 mmol/L) season cycles. The mean serum cholesterol concentration was significantly higher (P < 0.05) in the early rainy (3.7 ± 0.1 mmol/L) than in cold-dry (3.2±0.1 mmol/L) season cycles. There was no significant difference in mean serum total protein concentrations between the cold-dry and early rainy season cycles (cold-dry season: 64.6 +0.8 g/L vs early rainy season: 66.2±0.7 g/L; P>0.05). It is concluded that season but not oestrous cycle phase affects serum concentrations of some nutritional metabolites during the oestrous cycle in SB goats. It is therefore recommended that producers and clinicians should take into cognizance the seasonal variation in serum profiles of some energy substrates in feed formulation and reproductive herd health management in SB goats in the Northern Guinea Savannah zone of Nigeria. Keywords: Nutritional metabolites. Oestrous cycle, Season, Savannah Brown goats

UV-Vis Determination of Total Cholesterol in Various Tropical Poultry Meat Parts

The cholesterol contents of the different parts of tropical Gallus species were analyzed using UV-Vis spectrophotometer and results shows that in all the three species of Gallus studied, Gallus sonnratii’s intestine had the highest cholesterol content of 226.96 mg/100 g compared to the Gallus gallus and Gallus domesticus intestine with lower values of 215.65 mg/100 g and 177.39 mg/100 g respectively. Gallus gallus liver had the highest cholesterol content of 218.26 mg/100 g. However, Gallus sonnratii had the highest cholesterol content of 163.48 mg/100 g. In general, raw poultry meat has approximately 27 to 90 mg cholesterol/100 g and cooked poultry meat contains around 59 to 154 mg/100. A significant factor affecting cholesterol content of poultry is the type of retail cut because of the difference between dark and white chicken meat and the presence of skin in many retail cuts. Most importantly too, the extent of cholesterol in any meat part is indicative of the nature of the dietary.

A rapid quantitative UPLC-MS/MS method for analysis of key regulatory oxysterols in biological samples for liver cancer

An UPLC-APCI-MS/MS method was developed for the simultaneous determination of cholesterol, 7-dehydrocholesterol (7DHC) and eight oxysterols including 27-hydroxycholesterol (27OHC), 7α-hydroxycholesterol (7αOHC), 7β-hydroxycholesterol (7βOHC), 24S-hydroxycholesterol (24SOHC), 25-hydroxycholesterol (25OHC), 7α,24S-dihydroxycholesterol (7α,24SdiOHC), 7α,25-dihydroxycholesterol (7α,25diOHC), and 7α,27-dihydroxycholesterol (7α,27diOHC). It has been used for quantitative analysis of cholesterol, 7DHC and eight oxysterols in hepatocellular carcinoma (HCC) cells, plasma and tumor tissue samples. And the above compounds were extracted from the biological matrix (plasma and tissue) using liquid-liquid extraction with hexane/isopropanol after saponification to cleave the steroids from their esterified forms without further derivatization. Then cholesterol, 7DHC and oxysterols were separated on a reversed phase column (Agilent Zorbax Eclipse plus, C18) within 8 min using a gradient elution with 0.1 % formic acid in H2O and methanol and detected by an APCI triple quadrupole mass spectrometer. The lower limit of quantification (LLOQ) of the cholesterol, 7DHC and oxysterols ranged from 3.9 ng/mL to 31.25 ng/mL, and the recoveries ranged from 83.0 % to 113.9 %. Cholesterol, 7DHC and several oxysterols including 27OHC, 7αOHC and 7βOHC were successfully quantified in HCC cells, plasma, tissues and urine of HCC mice. Results showed that 27OHC was at high levels in three kind of HCC cells and tumor tissues as well as plasma samples from both HepG2 and Huh7 bearing mice model，and the high levels of 27OHC in tumors were associated with HCC development. Moreover, the levels of cholesterol in HCC cells and tumor issues varied in different HCC cells and mice model. Oxysterols profiling in biological samples might provide complementary information in cancer diagnosis.

Does LDL-C determination method affect statin prescribing for primary prevention? A register-based study in Southern Denmark.

Examine whether the low-density lipoprotein cholesterol (LDL -C) determination method influences the rate of statin initiation for primary prevention of cardiovascular disease. We conducted a register-based retrospective study in the Region of Southern Denmark. Two hospital-based laboratories in the region directly measure LDL -C whereas four laboratories calculate LDL -C using Friedewald's formula. Physicians do not choose which method is used. We included all statin-naïve patients ≥40 years with no history of cardiovascular disease, diabetes, or chronic kidney disease, who had their LDL -C determined during 2018-2019. There were 202807 people who had LDL -C determined during the study period (median age 59 years, 44% women) of which 37% had a direct LDL -C measurement. The median reported LDL -C was 3.40mmol/L [interquartile range (IQR) 2.90-4.00] for those with a direct measurement vs. 3.00mmol/L (IQR 2.40-3.50) for those with calculated LDL -C. For those with direct measurement, re-calculated LDL -C (using Friedewald's formula) was 0.35mmol/L lower than the reported direct LDL -C measurement. Among those with directly measured LDL -C, 3.6% initiated statins compared with 2.7% of those with a calculated LDL -C. Direct LDL -C measurement led to higher odds of having a statin initiated compared with calculated LDL -C (adjusted odds ratio 1.23, 95% CI 1.17-1.30); for those with triglycerides >1.7mmol/L the adjusted odds ratio was 1.41 (95% CI 1.30-1.52). Differences in the reporting of LDL -C from laboratories using different methods have a substantial influence on physician's decisions to prescribe statins.

A Sensitive Enzymatic Electrochemical Biosensor for Cholesterol Based on Cobalt Ferrite@Molybdenum Disulfide/Gold Nanoparticles.

Cholesterol is essential in biological systems, and the level of cholesterol in the body of a person acts as a diagnostic marker for a variety of diseases. So, in this work, we fabricated an enzymatic electrochemical biosensor for cholesterol using cobalt ferrite@molybdenum disulfide/gold nanoparticles (CoFe2O4@MoS2/Au). The synthesized composite was used for the determination of cholesterol by voltametric methods. The electroactive material CoFe2O4@MoS2/Au was successfully verified from the physiochemical studies such as XRD, Raman, FT-IR, and XPS spectroscopy along with morphological FESEM and HRTEM characterization. CoFe2O4@MoS2/Au showed outstanding dispersion in the aqueous phase, a large effective area, good biological compatibility, and superior electronic conductivity. The microflower-like CoFe2O4@MoS2/Au was confirmed by scanning electron microscopy. The image of transmission electron microscopy showed decoration of gold nanoparticles on CoFe2O4@MoS2 surfaces. Furthermore, a one-step dip-coating technique was used to build the biosensor used for cholesterol detection. In addition to acting as an enabling matrix to immobilize cholesterol oxidase (ChOx), CoFe2O4@MoS2/Au contributes to an increase in electrical conductivity. The differential pulse voltammetry method was used for the quantitative measurement of cholesterol. The calibration curve for cholesterol was linear in the concentration range of 5 to 100 μM, with a low limit of detection of 0.09 μM and sensitivity of 0.194 μA μM-1 cm-2. Furthermore, the biosensor demonstrates good practicability, as it was also employed for identifying cholesterol in real samples with acceptable selectivity and stability.

High-sensitive detection of H2O2 in biological systems by persistent luminescent nanoprobes

Autofluorescence interference in the conventional fluorescence detection of hydrogen peroxide (H2O2) in biological systems represents a long-lasting problem in the field of biosensing. Here, we report a Cr3+, Y3+ co-doped ZnGaSnO4 (ZGSCY) nanoprobes which show long persistent luminescence (PL) that can be specifically enhanced by H2O2 without background fluorescence interference. The mesoporous organosilica are coated on the surface of ZGSCY to enhance the biocompatibility of the nanoprobes. Importantly, PL intensity of the nanoprobes can be further improved, because of the specific response of tetrasulfide bond in organosilica to H2O2. ZGSCY@MON show high-sensitive detection of H2O2 in living cells and human serum with the advantages of high specificity, low detection limit (91 nM), and wide linear range (0.5–60 μM, 60–400 μM). Furthermore, the extraordinary detection capability of H2O2 enables that the successful differentiate normal breast cells from breast cancer cells and the highly sensitive determination of serum glucose and cholesterol. We also clarified that the endogenous response originates from the UV-induced the interfacial electron transfer on ZGSCY regulated by H2O2 and exogenous response stems from the elimination of the adsorption of PL from the organosilica by H2O2. These findings open up a new effective way for autofluorescence-free detection of H2O2 in biological systems.

Importance in the determination of serum uric acid, cholesterol and triglyceride levels in pregnant women

The fundamental importance of the analytes lies in their role as primary biomarkers to identify possible conditions that may arise during the gestation process. Objective: To analytes the importance of determining uric acid, cholesterol and triglycerides in pregnant women. Methodology: The article was a literature review that focused on the synthesis and analysis of scientific articles related to the topic in question. The PRISMA method was used to search for information, which consisted of an exhaustive and systematic search for relevant data using appropriate search terms and strategies. Results: Thirteen articles were screened and selected for analysis, of which six were excluded because they focused on pregnant women, but with different analytes. From the standards, 7 articles were identified that met the methodology and were included in the article development analysis. Conclusions: The research evidenced that the evaluation of uric acid, cholesterol and triglyceride levels are a first source in preclinical diagnosis, however, among the most common pathologies such as preeclampsia there are approximately 66 predictive parameters being this an important part of prenatal care to promote a healthy pregnancy

Reference Interval for Non-HDL-Cholesterol, Remnant Cholesterol and Other Lipid Parameters in the Southern Iranian Population; Findings From Bandare Kong and Fasa Cohort Studies.

Growing evidence shows the undisputable role of non-HDL-C and remnant cholesterol (remnant-C) in cardiovascular disease (CVD) risk assessment and treatment. However, the reference interval (RI) for these lipid parameters is not readily available. The aim of the present investigation was to determine the age and sex-specific RIs for non-HDL-C and remnant-C as well as other lipid parameters among a healthy population in southern Iran. We also report the RI of lipid parameters in rural and urban residents, smokers and post-menopausal women. Among 14063 participants of Bandare Kong and Fasa cohort studies, 792 healthy subjects (205 men and 578 women) aged 35-70 years were selected. Fasting blood samples were used for determination of total cholesterol (TC), triglycerides (TG) and HDL-C using colorimetric methods. Non-HDL-C and remnant-C were calculated using the valid formula. The 2.5th and 97.5th percentiles were calculated and considered as RI. In the total population (n=792, age 35-70), RIs for non-HDL-C and remnant-C was 74.0-206.8 and 8.0-52.7 mg/dL, respectively. Age (35-44 and≥45 years) and gender-specific RIs for serum non-HDL-C and remnant-C were determined. Remnant-C and non-HDL-C level were different between sex and age categories. The mean value of all lipid parameters except HDL-C was higher in men, urban residents, subject with age≥45 years and smokers. This is the first study in which the RIs for non-HDL-C and remnant-C in southern Iran are reported. This may help physicians to conveniently use these lipid parameters for patient care and better cardiovascular risk assessment.

A turn-on mode fluorescence detection of cholesterol based on calcein quenched by Co3O4 nanoclusters

Co3O4 nanoclusters (NCs) was prepared, and a novel method based on hydrogen peroxide (H2O2) mediated fluorescence recovery of calcein-Co3O4 NCs system for cholesterol detection was developed. The detection utilizes fluorescence quenching and recovery of calcein. In the absence of H2O2, the fluorescence of calcein is quenched by Co2+ ions on the surface of Co3O4 NCs. However, the fluorescence of calcein is restored in the presence of H2O2 as a result of the oxidation of Co2+ ions to Co3+ ions. Further investigation indicates tha Co3O4t there is a correlation between H2O2 concentration and fluorescence enhancement of calcein. Due to H2O2 being one of the products of cholesterol catalytic oxidation, a novel cholesterol fluorescence measurement method has been established, which can achieve sensitive detection of cholesterol in the range of 1.0–50 μM, with a limit of detection (LOD) as low as 0.48 μM. More importantly, the feasibility of the method was verified in human serum total cholesterol determination with satisfactory results, indicating its potential application in real sample analysis.

Lipid Profile of Meat Parts of Cow Slaughtered at Obinze Abattoir, Imo State, Nigeria

Meat, a vital component of human nutrition, offers essential nutrients for balanced diets and growth. However, it’s cholesterol and fatty acid (FA) compositions impact cardiovascular health. This study aimed to describe the cholesterol content and fatty acid profile in various cow meat parts. Samples from torso, stomach, skin, intestine and lean meat were collected from an abattoir in Obinze, Imo State, Nigeria. Analytical methods involved gas chromatography fitted with flame ionisation detector (GC-FID) for fatty acid profile and Liebermann-Burchard method for cholesterol determination. Cholesterol concentrations varied across the meat parts, with torso meat exhibiting the highest (115±6.48 mg/kg) and stomach meat the lowest (67.76±5.69 mg/kg). Saturated fatty acids (SFAs) like stearic and palmitic acids were prominent. The monounsaturated fatty acid, oleic acid presented various concentrations: skin (26.19±2.00 mg/kg), torso (24.33±5.50 mg/kg), lean meat (13.10±1.30 mg/kg), stomach (12.511±2.91 mg/kg) and intestine (4.02±0.86 mg/kg). Meat parts contained fatty acids that are beneficial to human health not only in terms of essential fatty acids such as linoleic and alpha-linolenic acids, but also the polyunsaturated fatty acids, arachidonic, eicosapentaenoic and docosahexanoic acids. An understanding of these compositional variations provides valuable insights for shaping dietary choices and reducing cardiovascular risks associated with elevated cholesterol levels.

A General Review of Methodologies Used in the Determination of Cholesterol (C27H46O) Levels in Foods.

Cholesterol (C27H46O) is a lipid-derived substance found in lipoproteins and cell membranes. It is also one of the main sources for the production of bile acids, vitamin D, and steroid hormones. Today, foods are evaluated by consumers not only according to their taste and nutritional content but also according to their effects on consumer health. For example, many consumers choose foods according to their cholesterol level. The cholesterol in the food can directly affect the blood cholesterol level when consumed, which can lead to cardiovascular diseases. High levels of cholesterol can lead to diet-related human diseases such as cardiac arrest, paralysis, type II diabetes, and cerebral hemorrhage. In societies with high living standards, interest in and consumption of foods that lower or have low cholesterol levels have increased recently. Accordingly, efforts to increase the variety of foods with reduced cholesterol levels are on the rise. This has indirectly led to the accurate measurement of cholesterol levels in blood and food being of great importance. Classical chemical, enzymatic, colorimetric, polarographic, chromatographic, and spectrophotometric methods; enzymatic, nonenzymatic, and electrochemical sensors; and biosensors are used for the determination of cholesterol in foods. The purpose of this review is to reveal and explore current and future trends in cholesterol detection methods in foods. This review will summarize the most appropriate and standard methods for measuring cholesterol in biological components and foods.

Polydopamine on Copper-Doped Cerium Dioxide Nanosheets as Peroxidase Mimics for the Intelligent Detection of Cholesterol.

The catalytic ability of nanozymes has become an enzymology hotspot in the field of application. Most nanozymes were characterized to simultaneously have oxidase-like and peroxidase-like activities, but the practical application often focuses on certain activity; other complex activities may cause interference. The peroxidase-like activity (POD-like activity) of nanozymes have been widely used in the colorimetric detection of H2O2 or substances producing H2O2 as an intermediate, such as the detection of small biological molecules with the oxidative reaction of a chromogenic reagent in the presence of POD-like nanozymes. In this work, we used polydopamine (PDA) as the surface coating of Cu-CeO2 nanosheets (PDA@ Cu-CeO2), which enhanced peroxidase-like activity while inhibiting their oxidase-like activity, providing a feasible method for the sensitive determination of cholesterol by integrating visual colorimetric detection and a smartphone application as a readout. The absorbance intensity and RGB values displayed a linear range on cholesterol from 0.05 to 1.2 mM with the LOD (limit of detection) of 42.7 and 99.4 μM. In addition, the method is expected to apply in detecting cholesterol in human serum with acceptable accuracy.

Determination of Cholesterol by Colorimetry and Surface-Enhanced Raman Spectroscopy Using Gold Nanoparticles Decorated with a Fe(III)-Tetra(4-Carboxyphenyl)-Porphine Metal-Organic Framework

A simple and facile hydrothermal method was developed for the synthesis of gold nanoparticles (AuNPs) adorned with two-dimensional (2D) heme-like Fe(III)-tetra(4-carboxyphenyl)-porphine (TCPP-Fe) metal-organic framework (MOF) nanocomposite. Notably, the synthesized hybrid nanomaterial (AuNPs/TCPP-Fe hybrid nanosheets) exhibited excellent peroxidase (POD)-like nanoenzymes activity and Raman activity under ultrasound (US) and near-infrared (NIR) irradiation at physiological pH conditions. A cascade colorimetric-SERS dual-mode method was developed for sensitive and rapid cholesterol determination based on the excellent POD-like properties and surface-enhanced Raman spectroscopy (SERS) activity of AuNPs/TCPP-Fe nanoenzymes. The TCPP-Fe nanoenzymes combined with cholesterol oxidase catalyze a cascade reaction to convert cholesterol to H2O2, which then oxidizes colorless, low Raman-activity 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue, high-Raman-activity oxidation product (ox-TMB). The cholesterol in human serum of colorimetric-SERS was successfully assayed with good recovery from 97.8 to 103.7%. The study paves a new method for designing a nanocomposite-based SERS for biochemistry analysis.