Low Centrifugal Forces Research Articles

Development and validation of a portable device for lab-free versatile nucleic acid extraction.

Nucleic acid testing (NAT) has revolutionized diagnostics by providing precise, rapid, and scalable detection methods for diverse biological samples. These recent advancements satisfy the increasing demand for on-site diagnostics, yet sample preparation remains a significant bottleneck for achieving highly sensitive diagnostic assays. There is an unmet need for compatible, efficient, and lab-free sample preparation for point-of-care NAT. To address this, we developed a portable, lab-free, and battery-powered device for extracting nucleic acids. We explored using low centrifugal forces with existing commercial chemistry, demonstrating excellent performance. We designed and tested a battery-powered device to enable lab-free extractions, and verified reagents stored out to 6 months, suggesting exceptional deployment capabilities. We evaluated our device, comparing our results against those from a benchtop centrifuge across three types of samples: HIV RNA in buffer, HIV RNA in plasma, and SARS-CoV-2 RNA in saliva. The portable device demonstrated excellent agreement with the benchtop centrifuge, indicating high reliability. By providing an effective on-site sample preparation solution, the widespread adoption of low centrifugal extractions will improve the sensitivity and reliability of NAT and will positively impact other point-of-care technologies such as next generation sequencing (NGS), biomarker detection, and environmental monitoring.

Leukocytes within Autologous Blood Concentrates Have No Impact on the Growth and Proliferation of Human Primary Osteoblasts: An In Vitro Study.

Platelet-rich fibrin (PRF) is a widely used autologous blood concentrate in regenerative medicine. This study aimed to characterize the cellular composition and distribution of different PRF matrices generated by high (710 g) and low (44 g) relative centrifugal forces (RCFs) and to analyze their bioactivity on human primary osteoblasts (pOBs). PRF was separated into upper layer (UL) and buffy coat (BC) fractions, and their cellular contents were assessed using histological and immunohistochemical staining. The release of platelet-derived growth factor (PDGF) and transforming growth factor (TGF-β) was quantified using an ELISA. Indirect PRF treatment on pOBs was performed to evaluate cell viability and morphology. A histological analysis revealed higher quantities of leukocytes and platelets in the low-RCF PRF. TGF-β release was significantly higher in the low-RCF PRF compared to the high-RCF PRF. All PRF fractions promoted pOB proliferation regardless of the centrifugation protocol used. The low-RCF PRF showed higher TGF-β levels than the high-RCF PRF. These findings contribute to understanding the cellular mechanisms of PRF and provide insights into optimizing PRF protocols for bone regeneration, advancing regenerative medicine, and improving patient outcomes.

Platelet rich fibrin as a bioactive matrix with proosteogenic and proangiogenic properties on human healthy primary cells in vitro

Blood concentrates like platelet rich fibrin (PRF) have been established as a potential autologous source of cells and growth factors with regenerative properties in the field of dentistry and regenerative medicine. To further analyze the effect of PRF on bone tissue regeneration, this study investigated the influence of liquid PRF matrices on human healthy primary osteoblasts (pOB) and co-cultures composed of pOB and human dermal vascular endothelial cells (HDMEC) as in vitro model for bone tissue regeneration. Special attention was paid to the PRF mediated influence on osteoblastic differentiation and angiogenesis. Based on the low-speed centrifugation concept, cells were treated indirectly with PRF prepared with a low (44 g) and high relative centrifugal force (710 g) before the PRF mediated effect on osteoblast proliferation and differentiation was assessed via gene and protein expression analyses and immunofluorescence. The results revealed a PRF-mediated positive effect on osteogenic proliferation and differentiation accompanied by increased concentration of osteogenic growth factors and upregulated expression of osteogenic differentiation factors. Furthermore, it could be shown that PRF treatment resulted in an increased formation of angiogenic structures in a bone tissue mimic co-culture of endothelial cells and osteoblasts induced by the PRF mediated increased release of proangiogenic growth factors. The effects on osteogenic proliferation, differentiation and vascularization were more evident when low RCF PRF was applied to the cells. In conclusion, PRF possess proosteogenic, potentially osteoconductive as well as proangiogenic properties, making it a beneficial tool for bone tissue regeneration.

Measuring water holding capacity in poultry meat

In the current scientific literature, one can find >100 different methods to evaluate water-holding capacity in fresh and cooked meat. The main concepts are based on removing some of the water by either gravity, application of pressure (e.g., centrifugal force), and heating while measuring water exudate to predict the water holding capacity (WHC) during storage, processing, cooking, and/or distribution. More sophisticated methods include nuclear magnetic resonance (NMR) in which the relaxation of water molecules within a meat protein/gel system is measured to predict how the water (75% in lean meat) will behave during processing. Overall, the number of tests reported is also so high because there are quite big variations in test conditions (e.g., 750-30,000 g for centrifugal testing). The aim of this article (outcome of a symposium on methods for poultry meat characterization) is to help the reader navigate through the different setups and suggest standardized testing based on scientific principles. The recommended WHC test is the application of low centrifugal force (750 g so sample is not permanently deformed) to a protein gel, while the sample is placed on a screen platform to avoid reabsorbing the liquid separating during the slowing down of the centrifuge. It is also recognized that some meat samples (e.g., high in fat) might require a different g-force, so it is recommended to employ both the conditions mentioned above and the lab-specific conditions. Our overall goal should always be to increase uniformity in test procedures, which will enhance our capabilities to compare results among research groups.

Experimental screening of various asphaltene deposition inhibitors for utilization in flowlines

This study presents a systematic experimental screening approach to scrutinize the efficacy of various inhibitors for two distinct crude oils (named A and M). The crudes possessed relatively high asphaltene content suffering from asphaltene deposition issues in flowlines. For this purpose, a set of static and dynamic tests were conducted for 16 chemical inhibitors. Modified asphaltene dispersion test (ADT) was mainly used for synthetic oils of SM and SA, made up of crude oils M and A, respectively. The samples were later subjected to inhibitors to monitor their inhibition performance, and thermal stability. DBSA was observed to outperform other chemicals, with an efficiency of 97%. However, its applicability was limited in fields under consideration where both water production and asphaltene deposition occur simultaneously. Branched DBSA, palmitic acid, and phthalic acid, at 1000 ppm, showed 52%, 41%, and 39% efficiencies, respectively. A lower centrifugal force, applied during ADT, improved the efficiency of 110, a commercial chemical, by over 2.5 times to 71%, suggesting its superior dispersion capabilities over inhibition. Thus, it was revealed that the ADT-based method at strict centrifugal conditions would underestimate the performance of dispersants. Furthermore, using the modified ADT on crude oil M revealed that DBSA, branched DBSA, and phthalic acid, at 1000 ppm, had 74%, 65%, and 58% efficiencies, respectively. Time scan turbidimetry showed also 67%, 51%, 49%, and 42% suspension of particles after 80 min in the presence of 66.6 vol% n-C7 for DBSA, branched DBSA, dispersant 110, and phthalic acid. Finally, results obtained from the capillary deposition flow (CDF) test at 70 °C, showed that dispersant 110 would have the most promising performance since 50% reduction for pressure drop was experienced. This chemical is deemed suitable due to low efficiency of DBSA in cases where water would co-produced with oil.

Ball milling alters the extractability and colloidal state of oat proteins

Oat protein must be extractable to play a functional role in liquid and semi-solid foods. Also relevant in this context is the colloidal state of the extracted oat protein, which is however rarely considered. Here, the impact of ball milling of defatted oat whole meal (DOW) on its protein extractability, composition and colloidal state in water, in a 1.0 M NaCl solution and in a medium at pH 9.0 was investigated. Overall, ball milling caused a decrease in DOW particle size and an increase in protein extractability, i.e. the protein recovery in the supernatant after extraction and centrifugation. Interestingly, for both control and ball milled DOW, increasing the applied centrifugal force after extraction led to a decreased protein extractability. Thus, a fraction of proteins – mainly 12S globulins as revealed by chromatography – remained in suspension at lower centrifugal force but precipitated at higher centrifugal force. This effect was more pronounced for ball milled DOW. These findings indicate that part of the 12S globulins in oat protein extracts, especially after prior ball milling, occur as protein aggregates. In conclusion, ball milling and altered centrifugation conditions after extraction can result in oat extracts with pronounced differences in protein level, composition and colloidal state.

Bacterial extracellular vesicles and associated functional proteins in fermented dairy products with Lacticaseibacillus paracasei.

Cells of all kingdoms produce extracellular vesicles (EVs); hence, they are present in most environments and body fluids. Lacticaseibacillus paracasei produces EVs that have attached biologically active proteins (P40 and P75). In this study, EV and functional proteins were found in five different commercial dairy-fermented products carrying L. paracasei. Strains present in those products were isolated, and with one exception, all produced small EVs (24-47 d.nm) carrying P40 and P75. In order to winnow bacterial EV from milk EV, products were subjected to centrifugal fractionation at 15,000 × g (15 K), 33,000 × g (33 K), and 100,000 × g (100 K). P75 was present in all supernatants and pellets, but P40 was only found in two products bound to the 15 and 33 K pellets, and 16S rDNA of L. paracasei could be amplified from all 100 K EVs, indicating the presence of L. paracasei EV. To investigate the interactions of bacterial EV and proteins with milk EV, L. paracasei BL23 EV was added to three commercial UHT milk products. Small-size vesicles (50-60 d.nm) similar to L. paracasei BL23 EV were found in samples from 100 K centrifugations, but intriguingly, P40 and P75 were bound to EV in 15 and 33 K pellets, containing bovine milk EV of larger size (200-300 d.nm). Sequencing 16S rDNA bands amplified from EV evidenced the presence of bacterial EVs of diverse origins in milk and fermented products. Furthermore, L. paracasei 16S rDNA could be amplified with species-specific primers from all samples, showing the presence of L. paracasei EV in all EV fractions (15, 33, and 100 K), suggesting that these bacterial EVs possibly aggregate and are co-isolated with EV from milk. P40 and P75 proteins would be interacting with specific populations of milk EV (15 and 33 K) because they were detected bound to them in fermented products and milk, and this possibly forced the sedimentation of part of L. paracasei EV at lower centrifugal forces. This study has solved technically complex problems and essential questions which will facilitate new research focusing on the molecular behavior of probiotics during fermentation and the mechanisms of action mediating the health benefits of fermented products.

Functional evaluation of muscle-tendon repair in athletes treated with monomeric phase platelet-rich fibrin

The autologous platelet-rich fibrin in the monomeric phase (MP-PRF) is a matricellular product obtained from the selective separation of elements in the blood by centrifugation with very low relative centrifugal force, and it appears as a possible alternative in the treatment of muscle-tendon injuries caused by therapeutically functional molecules concentrate. The objective of this study was to verify the obtained concentration of leukocytes and platelets in the matrix according to the proposed centrifugation method (fibrin protocol) and to correlate it with the functional clinical condition in patients submitted to the application of this matrix. In the laboratory phase, according to the acquisition protocol, hemocytometry was performed with anticoagulated blood samples from 05 patients recruited from the sample universe of 14 participants, where the platelet concentration of 119.35% was higher than that observed in whole blood. For the clinical experimental phase, MP-PRF obtained from non-anticoagulated blood samples, were applied to pre-existing muscle-tendon injuries with more than 30 days of evolution in the 14 participants. For functional assessment, the validated DASH and LEFS were used. Of the 14 patients selected, 13 were athletes and showed significant functional improvement three weeks after the intervention. No complications resulted from the response. The infiltrations improved the functional clinical status of the patients. There were no cases of complications, revealing that the procedure is safe. New prospective clinical studies are needed to strengthen this new therapeutic modality.

Novel Gold Nanoparticle-Based Quick Small-Exosome Isolation Technique from Serum Sample at a Low Centrifugal Force.

Exosomes are cell-secreted vesicles secreted by a majority of cells and, hence, populating most of the biological fluids, namely blood, tears, sweat, swab, urine, breast milk, etc. They vary vastly in size and density and are influenced by age, gender and diseases. The composition of exosomes includes lipids, DNA, proteins, and coding and noncoding RNA. There is a significant interest in selectively isolating small exosomes (≤50 nm) from human serum to investigate their role in different diseases and regeneration. However, current techniques for small exosome isolation/purification are time-consuming and highly instrument-dependent, with limited specificity and recovery. Thus, rapid and efficient methods to isolate them from bio fluids are strongly needed for both basic research and clinical applications. In the present work, we explored the application of a bench-top centrifuge for isolating mostly the small exosomes (≤50 nm). This can be achieved at low g-force by adding additional weight to the exosomes by conjugating them with citrate-capped gold nanoparticles (CGNP). CGNPs were functionalized with polyethylene glycol (PEG) to form PEGylated GNP (PGNP). EDC/SNHS chemistry is used to activate the –COOH group of the PEG to make it suitable for conjugation with antibodies corresponding to exosomal surface proteins. These antibody-conjugated PGNPs were incubated with the serum to form PGNP-exosome complexes which were separated directly by centrifugation at a low g-force of 7000× g. This makes this technique efficient compared to that of standard ultracentrifugation exosome isolation (which uses approximately 100,000× g). Using the technique, the exosome isolation from serum was achieved successfully in less than two hours. The purification of small exosomes, characterized by the presence of CD63, CD9 and CD81, and sized between 20 nm to 50 nm, was confirmed by western blot, dynamic light scattering (DLS), transmission electron microscopy (TEM) and nanoparticle tracking analyser (NTA).

Rapidly Deployable Algae Cleaning System for Applications in Freshwater Reservoirs and Water Bodies

Occurrence of large-scale harmful algal blooms (HABs) in our reservoirs and water bodies threaten both quality of our drinking water and economy of aquaculture immensely. Hence, rapid removal of HAB biomass during and after a bloom is crucial in protecting the quality of our drinking water and preserve our water resources. We reported here a rapidly deployable algae cleaning system based on a high-capacity high-throughput (HCHT) spiral blade continuous centrifuge connected with inlet and effluent water tanks and a series of feed-in and feed-out pumps as well as piping, all fitted into a standard 20 feet metal shipping container. The system separates algal biomass from algae-laden water with a maximum flow rate of 4000 L/h and a centrifugal force of 4500× g. Cells collected by the system are still intact due to the low centrifugal force used. We showed that after HCHT centrifugation, cellular contents of HAB biomass were not found in the effluent water, and hence, could be discharged directly back to the water body. Furthermore, the addition of flocculants and chemicals prior to the separation process is not required. The system could operate continuously with proper programmed procedures. Taken overall, this system offered a much better alternative than the traditional flocculation- and sonication-based methods of HAB removal in a freshwater environment. This deployable system is the first of its kind being built and had been field-tested successfully.

A novel approach of harvesting concentrated plasma-rich fibrin (PRF) with increased platelet count

Objectives: Platelet-rich fibrin (PRF) is an autogenous biomaterial, considered as the second-generation platelet concentrates rich in blood cells and growth factors entrapped in the fibrin matrix, which makes it as an ideal material with wound healing abilities. Studies have reported high harvest of cells using anticoagulants but the present study employs two different protocols to efficiently separate the platelet-rich layer at low centrifugal forces without the use of anticoagulants. Material and Methods: Blood samples were collected with the consent of 20 volunteer donors. Ten blood samples were tested in each of the protocols studied, that is, protocol 1–200 g for 8 min (higher rpm and time) and protocol 2–60 g for 5 min (lower rpm and time). From the 12 ml of blood samples collected, 2 ml of blood was utilized for whole blood study; the remaining 10 ml was transferred into falcon tubes subjected to different rpm. Results: The present study employs a novel method to investigate segregation of cell types following low-grade centrifugation. One milliliter sequential pipetting technique was used to analyze number of leukocytes and platelets following centrifugation at two different g-forces. The protocols followed in the present study had 2–3-fold increase leukocytes concentration and 10–12-fold increases in platelet concentrations in the layers than the whole blood sample without the use of anticoagulants. Conclusion: The study concludes that protocol 1 was more efficient in harvesting platelets with less concentration of leukocytes, which is considered more suitable for various medical applications.

Sample preparation for the analysis of nanoparticles in natural waters by single particle ICP-MS

With the significant increase in the production and use of nanoparticles (NP), concern is increasing over their release into their environment. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is emerging as one of the best techniques for detecting the very small NP at very low concentrations in natural waters. However, there is no unified protocol for the preparation of natural water samples for SP-ICP-MS analysis. In order to minimize nebulizer blockage, filtration is often used with the expectation that 0.45 μm membranes will not remove significant quantities of 1–100 nm NP. Nonetheless, there are limited data on its effect on the concentrations or size distributions of the NP. To that end, we examined the interactions between six different membrane filters and silver (Ag) and cerium oxide (CeO2) NP in aqueous samples. For Ag NP, the highest recoveries were observed for polypropylene membranes, where 55% of the pre-filtration NP were found in rainwater and 75% were found in river waters. For CeO2 NP, recoveries for the polypropylene membrane attained 60% in rainwater and 75% in river water. Recoveries could be increased to over 80% by pre-conditioning the filtration membranes with a multi-element solution. Similar recoveries were obtained when samples were centrifuged at low centrifugal forces (≤1000×g).

Composition of flesh lipids and oleosome yield optimization of selected sea buckthorn (Hippophae rhamnoides L.) cultivars grown in Poland

Sea buckthorn berries contain lipids rich in palmitoleic acid, carotenoids, tocols and sterols, but their composition varies greatly depending on the cultivar and region of cultivation. Therefore, the current study presents the chemical composition of fruit flesh oils of cultivars grown in Poland and compares them with plants grown worldwide. Among tested cultivars, the highest shares of palmitoleic acid were determined in Golden Rain and Luczystaja cvs. Ten grams of sea buckthorn flesh oil provides at least 28% of vitamin A, 50% of vitamin E and 5% of sterols of the recommended dietary allowance (RDA) values for adults. The final part of this study is dedicated to a preliminary study of the optimization of the oleosome yield by the centrifugation method. The maximum oleosome yield can be obtained at a relatively low centrifugal force (below 8000×g), while optimal temperature and time should be laboratory determined for each cultivar.

Emulsifying properties of plasma fractionated from egg yolk using low centrifugal forces—Mayonnaise preparation

Egg yolk can be fractionated into two fractions, plasma and granule, at high centrifugation force. This work was designed to study the influence of using low centrifugal forces (2000 to 6,000 ×g) for a short time (5 min) on the fractionation efficiency. The chemical composition and emulsifying properties (oil droplet size and stability against creaming) of fractionated plasmas were also investigated. The results showed that the separation efficiency of granules was significantly increased with increasing centrifugal force. No significant difference was found in emulsifying properties of plasmas fractionated at all centrifugal forces compared to whole egg yolk. Plasma fractionated at 5,000 and 6,000 ×g was further applied for mayonnaise preparation. Mayonnaises prepared from plasmas showed no significant difference in the rheological and colorimetric properties compared to whole egg yolk. Plasma prepared from low centrifugal force, compatible to industrial setting, maintains its original emulsifying properties and is applicable for mayonnaise preparation. Novelty impact statement Although many years of research on fractionation of egg yolk fractions, industrial application of egg yolk fractions is rare. Literature information on this field was relied on high centrifugal forces of fractionation. The conditions we applied using low centrifugation forces are thus significant to help the industry realize the potential of value-addition to egg yolk component such as phosvitin in the granule while using the plasma fraction for its emulsifying property. The obtained results suggested that plasma prepared using low centrifugal forces showed comparable rheological properties and was applicable for preparing mayonnaise, which indicates its potential in future industry application.

Biologization of Pcl-Mesh Using Platelet Rich Fibrin (Prf) Enhances Its Regenerative Potential In Vitro.

Introduction: Resorbable synthetic scaffolds are promising for different indications, especially in the context of bone regeneration. However, they require additional biological components to enhance their osteogenic potential. In addition to different cell types, autologous blood-derived matrices offer many advantages to enhance the regenerative capacity of biomaterials. The present study aimed to analyze whether biologization of a PCL-mesh coated using differently centrifuged Platelet rich fibrin (PRF) matrices will have a positive influence on primary human osteoblasts activity in vitro. A polymeric resorbable scaffold (Osteomesh, OsteoporeTM (OP), Singapore) was combined with differently centrifuged PRF matrices to evaluate the additional influence of this biologization concept on bone regeneration in vitro. Peripheral blood of three healthy donors was used to gain PRF matrices centrifuged either at High (710× g, 8 min) or Low (44× g, 8 min) relative centrifugal force (RCF) according to the low speed centrifugation concept (LSCC). OP-PRF constructs were cultured with pOBs. POBs cultured on the uncoated OP served as a control. After three and seven days of cultivation, cell culture supernatants were collected to analyze the pOBs activity by determining the concentrations of VEGF, TGF-β1, PDGF, OPG, IL-8, and ALP- activity. Immunofluorescence staining was used to evaluate the Osteopontin expression of pOBs. After three days, the group of OP+PRFLow+pOBs showed significantly higher expression of IL-8, TGF-ß1, PDGF, and VEGF compared to the group of OP+PRFHigh+pOBs and OP+pOBs. Similar results were observed on day 7. Moreover, OP+PRFLow+pOBs exhibited significantly higher activity of ALP compared to OP+PRFHigh+pOBs and OP+pOBs. Immunofluorescence staining showed a higher number of pOBs adherent to OP+PRFLow+pOBs compared to the groups OP+PRFHigh+pOBs and OP+pOBs. To the best of our knowledge, this study is the first to investigate the osteoblasts activity when cultured on a PRF-coated PCL-mesh in vitro. The presented results suggest that PRFLow centrifuged according to LSCC exhibits autologous blood cells and growth factors, seem to have a significant effect on osteogenesis. Thereby, the combination of OP with PRFLow showed promising results to support bone regeneration. Further in vivo studies are required to verify the results and carry out potential results for clinical translation.

Separation of aggregated β-lactoglobulin with optimised yield in a decanter centrifuge

The interest in individual whey protein fractions, especially the main proteins α-lactalbumin and β-lactoglobulin, has been growing due to their unique nutritional value and their exceptional technofunctional properties. Various fractionation and purification methods have been published. However, none of them achieved highest purity, maximal recovery, and transferability to industrial scale. This study used thermal treatment for selective aggregation of β-lactoglobulin, which was subsequently separated in a pilot-scale decanter centrifuge from the α-lactalbumin-enriched centrate. The aim was to investigate if the centrifugal separation can be improved by pH-induced flocculation of the aggregates compared with non-flocculated suspensions at pH 7.0. With various analytical methods, it was demonstrated that the strongest flocculation occurred at pH 4.4 and facilitated separation of aggregate fragments sized below 20 μm. Finally, separation efficiencies of more than 99% were achieved by aggregate flocculation in the pilot-scale decanter even at low centrifugal forces.

Development of a method for determining oil absorption capacity in pulse flours and protein materials

AbstractBackground and objectivesThe conventional method for determining oil absorption capacity (OAC) in pulse ingredients involves mixing a sample with excess oil, centrifuging the dispersion, and then calculating the amount of oil absorbed. However, there are issues associated with the conventional method such as loss of the less dense materials through oil decanting process and reabsorption of oil by samples after centrifugation. Therefore, the objective of this work was to develop a method that could eliminate those concerns for determining OAC.FindingsA method for measuring OAC of flours or protein concentrates/isolates derived from pulses and soybeans was developed. The new method involved mixing 0.5 g sample with 1.5 ml canola oil intermittently for 20 min, centrifuging the inverted sample tubes at 600 ×g for 25 min, and measuring the amount of oil absorbed per gram of dry sample. Comparing to the conventional method, the new method used a lower sample to oil ratio (1:3 g/ml), and each test tubes were centrifuged upside down in an apparatus at a lower centrifugal force (600 ×g). A syringe barrel was used in the apparatus to hold a filter paper in place to prevent sample materials from draining out with the excess oil during centrifugation. Test efficiency increased due to combining steps of centrifugation and oil draining in the new method. Differences in OAC values determined by the new method were exhibited from various pulse and soybean materials.ConclusionsAmounts of oil absorbed by flours and protein concentrates/isolates from pulses and soybeans could be measured by the new method without accounting for the extra free oil trapped in the samples. The new procedure showed good within‐laboratory reproducibility. More samples could be tested with the new method due to its simplified procedure. Flours and protein concentrates/isolates from pulses and soybeans with different OAC values could be separated from each other using the new method.Significance and noveltyThe method developed was simple and reliable and could be applied to a variety of pulse and soybean ingredients.

Stability of the Human Plasma Proteome to Pre-analytical Variability as Assessed by an Aptamer-Based Approach.

Variable processing and storage of whole blood and/or plasma are potential confounders in biomarker development and clinical assays. The goal of the study was to investigate how pre-analytical variables impact the human plasma proteome. Whole blood obtained from 16 apparently healthy individuals was collected in six EDTA tubes and processed randomly under six pre-analytical variable conditions including blood storage at 0 °C or RT for 6 h (B6h0C or B6hRT) before processing to plasma, plasma storage at 4 °C or RT for 24 h (P24h4C or P24hRT), low centrifugal force at 1300 × g, (Low×g), and immediate processing to plasma under 2500 × g (control) followed by plasma storage at -80 °C. An aptamer-based proteomic assay was performed to identify significantly changed proteins (fold change ≥1.2, P < 0.05, and false discovery rate < 0.05) relative to the control from a total of 1305 proteins assayed. Pre-analytical conditions Low×g and B6h0C resulted in the most plasma proteome changes with 200 and 148 proteins significantly changed, respectively. Only 36 proteins were changed under B6hRT. Conditions P24h4C and P24hRT yielded changes of 28 and 75 proteins, respectively. The complement system was activated in vitro under the conditions B6hRT, P24h4C, and P24hRT. The results suggest that particular pre-analytical variables should be controlled for clinical measurement of specific biomarkers.

The Impact of Duration and Force of Centrifugation on Platelet Content and Mass in the Preparation of Platelet-Rich Plasma.

Platelet-rich plasma (PRP) is an autologous prepared plasma enriched with platelets and obtained after a centrifugal separation and aggregation procedure. However, the optimized preparation protocol for PRP is still controversial and there are no standardized preparation protocols. The aim of this study is to show the effect of time and force of the centrifugation on the concentrations of platelets and to optimize the effective PRP preparation protocol. For the study, whole blood was drawn into 24 different 6-ml standard tubes containing 0.6ml anticoagulant citrate dextrose solution-formula A. The samples were centrifuged separately at forces of 45×g, 180×g, 400×g, 725×g, 1130×g and 1630×g for 5, 10, 15 and 20min. Every sample was analyzed, and a comparison was made between all groups. No significant difference was observed in terms of platelet concentration, mean platelet volume or platelet mass between all groups (p > 0.05). The mean ± SD of platelet mass in baseline is 1890 ± 134 × 103fL/μL. The mean ± SD of platelet mass in the high centrifugal force of 1630×g was 3395 ± 564 × 103fL/μL, 2638 ± 425 × 103fL/μL, 2355 ± 449 × 103fL/μL and 2109 ± 41 × 103fL/μL over times of 5, 10, 15 and 20min, respectively. The mean ± SD of platelet mass in the low centrifugal force of 45×g was 2002 ± 1623 × 103fL/μL, 2491 ± 1591 × 103fL/μL, 2611 ± 876 × 103fL/μL and 3003 ± 511 × 103/μL over times of 5, 10, 15 and 20 min, respectively. Platelets should be evaluated with platelet mass not including platelet concentrations alone, but also with mean platelet volume, which symbolizes the size of platelets while comparing platelet-rich plasma preparation protocols and kits. This could be a new starting point for comparison of PRP for all applications in the literature. All centrifugation forces and times could produce biologically reactive PRP. It may be only suggested that if high acceleration force is used, low durations should be selected, or if low acceleration force is used, long time of centrifugation should be selected. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Centrifugal fractionation of softwood extracts improves the biorefinery workflow and yields functional emulsifiers

Centrifuging softwood extracts separated the hemicellulose-rich fraction and lignin-rich micro- and nanoparticles. The hemicellulose-rich fraction and lignin-rich nanoparticles formed stable emulsions.