DBS were shipped to the Malaria Laboratory, at the Centers for Disease Control and Prevention, Atlanta, under ambient temperature. A 6 mm punch of each sample was taken and eluted in blocking buffer containing: PBS, 0.5% polyvinyl alcohol (Sigma, St. Louis, MO), 0.8% polyvinylpyrrolidine (Sigma), 0.1% casein (ThermoFisher Scientific, Waltham, MA), 0.5% BSA (Sigma), 0.3% Tween-20, 0.05% sodium azide, and 0.01% E. coli extract to prevent non-specific binding. The elution step diluted the samples to a 1:20 × whole blood dilution, which was the dilution used for the assay. DBS samples were screened by a bead-based multiplex antigen assay for the simultaneous detection of P. falciparum HRP2 (HRP2), pan-Plasmodium aldolase (aldolase), and pan-Plasmodium lactate dehydrogenase (pLDH) based on previously-described protocol [41 (link)]. Antibodies used to detect epitopes on HRP2 also targeted the same epitopes on the HRP3 antigen.
Polyvinylpyrrolidine
Manufactured by Merck Group
Sourced in United States, United Kingdom
Polyvinylpyrrolidine is a synthetic polymer used in various laboratory applications. It serves as a stabilizer, binder, and dispersant in a range of scientific and industrial processes.
Automatically generated - may contain errors
Lab products found in correlation
Polyvinyl alcohol (pva), by Merck Group (5 mentions)
Bovine serum albumin (bsa), by Merck Group (4 mentions)
Casein, by Thermo Fisher Scientific (4 mentions)
Folin ciocalteu reagent, by Merck Group (1 mentions)
Chlorogenic acid, by Merck Group (1 mentions)
Ferulic acid, by Merck Group (1 mentions)
P coumaric acid, by Merck Group (1 mentions)
Sodium hydroxide (naoh), by Merck Group (1 mentions)
Sodium carbonate, by Merck Group (1 mentions)
Boric acid, by Merck Group (1 mentions)
2 mercaptoethanol, by Merck Group (1 mentions)
P hydroxybenzoic acid, by Merck Group (1 mentions)
Dna extraction kit, by Qiagen (1 mentions)
Pluronic f68, by Merck Group (1 mentions)
Chymotrypsinogen, by Merck Group (1 mentions)
Alginic acid sodium salt, by Merck Group (1 mentions)
Aspirin, by Merck Group (1 mentions)
Atenolol, by Merck Group (1 mentions)
Hydrochlorothiazide, by Merck Group (1 mentions)
Lactose, by Merck Group (1 mentions)
7 protocols using polyvinylpyrrolidine
1
DBS Multiplex Antigen Detection Assay
2
Characterizing Antioxidant Profile of Carrots
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Carrots cultivar Legend, which were grown in California (Grimmway Farms, Bakersfield, CA, USA) were examined. This cultivar is commonly used for processing by the fresh produce industry. To decrease variability, all carrots used in the experiment were approximately the same size and were inspected for any visual damage because any injury prior to processing could induce PAL activity. The selected carrots were stored in a 15 °C room until they were ready to be processed.
All chemicals and standards used: Folin-Ciocalteu reagent, sodium carbonate (Na2CO3), Trolox and 2,2-diphenyl-1-picrylhydrazyl (DPPH), polyvinylpyrrolidine (PVPP), sodium hydroxide (NaOH), boric acid, 2-mercaptoethanol, chlorogenic acid, p-hydroxybenzoic acid, p-coumaric acid, and ferulic acid were purchased from Sigma Chemical Co. (St. Louis, MO, USA). Methanol and acetonitrile were reagents of HPLC grade.
All chemicals and standards used: Folin-Ciocalteu reagent, sodium carbonate (Na2CO3), Trolox and 2,2-diphenyl-1-picrylhydrazyl (DPPH), polyvinylpyrrolidine (PVPP), sodium hydroxide (NaOH), boric acid, 2-mercaptoethanol, chlorogenic acid, p-hydroxybenzoic acid, p-coumaric acid, and ferulic acid were purchased from Sigma Chemical Co. (St. Louis, MO, USA). Methanol and acetonitrile were reagents of HPLC grade.
3
DBS Extraction and Antigen Detection
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Upon arrival at CDC, DBS were carefully examined for potential contamination by mold growth and sufficient blood volume (enough for two 6 mm punches) before elution of blood and DNA extraction. For antigen detection, samples were eluted in a blocking buffer (Buffer B: 0.5% Polyvinyl alcohol (Sigma) 0.5% polyvinylpyrrolidine (Sigma), 0.1% casein (ThermoFisher), 0.5% BSA (Sigma), 0.3% Tween-20, 0.05% sodium azide, and 0.01% E. coli extract to prevent non-specific binding) to a final concentration of 1:20×. Genomic DNA for molecular analysis was extracted from two 6 mm punches of the filter paper blood spots using the Qiagen DNA extraction kit following the manufacturer’s instructions for blood dried on filter paper (QIAGEN, Valencia, CA). The DNA was eluted in 150 μL of elution buffer, aliquoted, and stored at − 20 °C until further use.
4
Multiplex Antigen Assay for Malaria
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A single 6 mm punch of each sample was taken and eluted in blocking buffer containing: phosphate buffered saline (PBS, pH 7.2), 0.5% polyvinyl alcohol (Sigma, St. Louis, MO), 0.8% polyvinylpyrrolidine (Sigma), 0.1% casein (ThermoFisher Scientific, Waltham, MA), 0.5% BSA (Sigma), 0.3% Tween-20, 0.05% sodium azide, and 3 µg/mL Escherichia coli extract. Elution from filter paper diluted the samples to a 1:20 whole blood.
For detection of Plasmodium antigens, DBS samples were screened by a bead-based multiplex antigen assay for the simultaneous detection of P. falciparum HRP2 (HRP2), pan-Plasmodium aldolase (aldolase), and pan-Plasmodium lactate dehydrogenase (pLDH) based on previously described protocol [13 (link), 17 (link)]. To convert from assay signal to antigen concentration, equations were derived from standard curves of purified recombinant HRP2 antigen (Type B, Microcoat Biotechnologie GmbH, Bernried, Germany) as described previously [18 (link)].
For detection of Plasmodium antigens, DBS samples were screened by a bead-based multiplex antigen assay for the simultaneous detection of P. falciparum HRP2 (HRP2), pan-Plasmodium aldolase (aldolase), and pan-Plasmodium lactate dehydrogenase (pLDH) based on previously described protocol [13 (link), 17 (link)]. To convert from assay signal to antigen concentration, equations were derived from standard curves of purified recombinant HRP2 antigen (Type B, Microcoat Biotechnologie GmbH, Bernried, Germany) as described previously [18 (link)].
5
Dried Blood Spot Antibody Assay
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For the antibody and antigen detection assays, whole blood was eluted from a single tab of the TropBio filter wheels to provide sample for assay. A single DBS tab (10 μL whole blood) was rehydrated in a blocking buffer (PBS pH 7.2, 0.5% Polyvinyl alcohol (SigmaAldrich, St. Louis, MO) 0.5% polyvinylpyrrolidine (SigmaAldrich), 0.1% casein (ThermoFisher, Waltham, MA), 0.5% bovine serum albumin (SigmaAldrich), 0.3% Tween-20, 0.05% sodium azide, and 0.01% E. coli extract to prevent non-specific binding) to a final dilution of 1:20. Eluted blood samples were stored at 4°C until assayed.
6
Preparation of Biopolymer-Based Formulations
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2.1. Chemical: Alginic acid sodium salt (Alg), guar gum (GG), epichlorohydrin, polyvinyl pyrrolidine (PVP), Pluronic F68® (P68), polyvinyl alcohol (PVA) and chymotrypsinogen (QTg) were purchased from Sigma-Aldrich and used without further purification. All other reagents were also of analytical grade. The solutions were prepared with distilled water.
7
Pharmaceutical Formulation Development
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Ramipril and pravastatin sodium were supplied by Kemprotec Limited (Cumbria, UK). Atenolol, aspirin, and hydrochlorothiazide, polyvinylpyrrolidine (PVP) and lactose were supplied by Sigma-Aldrich (Gillingham, UK). D-mannitol 99 % was purchased from VWR International Ltd.
(Leicestershire, UK). Sodium starch glycolate (Primojel ® ) was kindly supplied as a gift from DFE Pharma. Hydroxypropyl methylcelloluse (HPMC K100M CR) (Methocel TM) was a gift from Colorcon ® . Milli-Q water (resistivity 18.2 MΩ cm) was used for all formulations and solutions. All other reagents were of either HPLC or analytical grade.
(Leicestershire, UK). Sodium starch glycolate (Primojel ® ) was kindly supplied as a gift from DFE Pharma. Hydroxypropyl methylcelloluse (HPMC K100M CR) (Methocel TM) was a gift from Colorcon ® . Milli-Q water (resistivity 18.2 MΩ cm) was used for all formulations and solutions. All other reagents were of either HPLC or analytical grade.
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