Concentration Of Microspheres Research Articles

Ingestion of polyethylene microspheres occur only in presence of prey in the jellyfish Aurelia aurita

Microplastic ingestion was studied in A. aurita, a bloom-forming, circumglobal medusa. Here, we determined whether factors such as the concentration of polyethylene microspheres (75–90 μm) or the absence/presence of prey affect the ingestion, duration of microspheres in the gastrovascular cavity (time of presence), and retention time. The presence of polyethylene microspheres' was determined by exposing medusae during 480 min to three different treatments (5000, 10,000, 20,000 particles L−1), and was checked every 10 min to ascertain whether they had incorporated any. Preliminary results show that microsphere ingestion occurred only in the presence of prey (⁓294 Artemia nauplii L−1). The time of presence of microbeads in A. aurita increased (103, 177, and 227 min), with increasing microplastic concentration, and the microbeads were egested within 150 min.This study initiates the understanding of the potential implications that arise of the encounter between jellyfish and microplastic agglomerates, and with perspectives for future research.

Laser Activated and Electroless Metalized Polyurethane Coatings Containing Copper(II) L-Tyrosine and Glass Microspheres.

Polyurethane coatings containing copper(II) L-tyrosine and glass microspheres were laser irradiated and underwent electroless metallization. Various sizes of glass microspheres were incorporated into the polyurethane coating matrix in order to examine their effects on surface activation and electroless metallization. The surface of the coatings was activated by using ArF excimer laser emitting ultraviolet radiation (λ = 193 nm) using different number of laser pulses and their fluence. The effects of surface activation and metallization were evaluated mainly based on optical and scanning electron microcopies (SEM), energy-dispersive X-ray spectroscopy (EDX) and photoelectron spectroscopy (XPS). It was found that the presence of glass microspheres enabled the reduction in copper complex content, intensified the ablation process (higher cone-like structures created) and resulted in higher content of copper metallic seeds. On the other hand, the glass microspheres concentration, which was higher for lower size microspheres, was advantageous for obtaining a fully metallized layer.

The preparation and study on properties of calcium sulfate bone cement combined tuning silk fibroin nanofibers and vancomycin-loaded silk fibroin microspheres.

In this study, a bioactive composite material based on calcium sulfate hemihydrate (CSH) bone cement was studied, which use calcium sulfate dihydrate (CSD) as coagulant and silk fibroin nanofibers (SFF) solution as the curing liquid, further loaded vancomycin silk fibroin microspheres (SFM/VCM). The drug release effect of bone cements caused by tuning weight content of SFM/VCM (0.5, 1, 2%) and the concentration of silk fibroin solution (SFS) (20, 60, 100 mg/mL) used for preparation of SFM was studied in this article. Scanning electron microscope (SEM) demonstrated that the average diameter of microspheres gradually increased and the setting time was prolonged with the concentration of SFS increasing. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) were used to analyze the composition of composite materials. The result of compressive strength revealed that the composites contained 0.5% SFM/VCM showed better mechanical performance independent on the concentration of microspheres and the cumulative drug release percentage of all composites were less than 55% after 4 weeks. The drug-loading bone cement possesses not only injectability but also sustained release capability which has a promising prospect in the field of bone substitute material.

Characterizing the aggressiveness of prostate cancer using an all-optical needle photoacoustic sensing probe: feasibility study.

In our previous studies, we have developed a prototype interstitial needle sensing probe that can acquire broadband A-line photoacoustic (PA) signals encoding both tissue microarchitecture and histochemical information comparable to that accessible by histology. Paving the road toward clinical translation of this technology, we replaced the piezoelectric hydrophone in the needle PA probe with a fiber optic hydrophone that enabled both broader bandwidth and sufficient signal-to-noise ratio (SNR) for PA signal detection. Such an all-optical design also facilitated disposability and significantly reduced the footprint of the needle PA sensing probe. Experiments were performed on well-controlled phantoms and human prostate tissues. The microarchitectures in each sample were quantitatively evaluated by both the nonlinear spectral slope of the PA signal power spectrum and the generalized gamma (GG) parameter a by implementing envelope statistics to the PA signal. In the studies on phantoms containing optically absorbing microspheres with various sizes and concentrations, the nonlinear spectral slope showed a strong correlation of r=-0.80 with the microsphere dimensions, and a relatively weak correlation of r=-0.54 with the microsphere concentrations, while the GG parameter a showed a strong correlation with the microsphere dimensions (r=0.72) and a moderate correlation with the microsphere concentrations (r=0.63). In the studies on human prostate tissues containing progressive cancer stages, both the nonlinear spectral slope and the GG parameter a demonstrated a statistically significant difference between benign and nonaggressive cancer tissues (p<0.01), and between nonaggressive and aggressive cancer tissues (p<0.01). In addition, a multivariate analysis combining the two quantitative measurements demonstrated the boundaries among the different progressive stages of prostate cancer.

Direct ingestion, trophic transfer, and physiological effects of microplastics in the early life stages of Centropristis striata, a commercially and recreationally valuable fishery species

Microplastics are ubiquitous in marine and estuarine ecosystems, and thus there is increasing concern regarding exposure and potential effects in commercial species. To address this knowledge gap, we investigated the effects of microplastics on larval and early juvenile life stages of the Black Sea Bass (Centropristis striata), a North American fishery. Larvae (13–14 days post hatch, dph) were exposed to 1.0 × 104, 1.0 × 105, and 1.0 × 106 particles L−1 of low-density polyethylene (LDPE) microspheres (10–20 μm) directly in seawater and via trophic transfer from microzooplankton prey (tintinnid ciliates, Favella spp.). We also compared the ingestion of virgin and chemically-treated microspheres incubated with either phenanthrene, a polycyclic aromatic hydrocarbon, or 2,4-di-tert-butylphenol (2,4-DTBP), a plastic additive. Larval fish did not discriminate between virgin or chemically-treated microspheres. However, larvae did ingest higher numbers of microspheres through ingestion of microzooplankton prey than directly from the seawater. Early juveniles (50–60 dph) were directly exposed to the virgin and chemically-treated LDPE microspheres, as well as virgin LDPE microfibers for 96 h to determine physiological effects (i.e., oxygen consumption and immune response). There was a significant positive relationship between oxygen consumption and increasing microfiber concentration, as well as a significant negative relationship between immune response and increasing virgin microsphere concentration. This first assessment of microplastic pollution effects in the early life stages of a commercial finfish species demonstrates that trophic transfer from microzooplankton can be a significant route of microplastic exposure to larval stages of C. striata, and that multi-day exposure to some microplastics in early juveniles can result in physiological stress.

Distribution improvement of etch tunnels on aluminum foil coated by Al2O3 film doped with ZnO microspheres

In this paper, a Al2O3 film doped with ZnO microspheres was successfully fabricated on aluminum foil by the sol-gel method. In order to improve the distribution of etched tunnels, the effects of Al2O3 film doped with ZnO microspheres on the surface morphology and electrochemical properties of aluminum foil were investigated. The results showed that, with a suitable concentration of Al2O3 film and ZnO microspheres, uniform distribution of etched tunnels could be obtained on the aluminum foil after the electrochemical etching. When the concentration of Al2O3 film and ZnO microspheres are 0.1 mol/L and 0.02 mol/L, respectively, the specific capacitance of the etched aluminum foil achieved the maximum. The above beneficial results were attributed to the improvement in pitting initiation sites on the aluminum foil coated by Al2O3 film doped with ZnO microspheres, which was supported by the experimental results of surface morphology and electrochemical testing. The etching mechanism was related to the dissolution of ZnO microspheres, the replacement of Zn crystal nucleus and the formation of active sites for pitting corrosion. This paper provides experimental and theoretical insights into the distribution improvement of etch tunnels, showing a significant engineering value for process design and properties optimization for aluminum foils.

The short-term safety and efficacy of TANDEM microspheres of various sizes and doxorubicin loading concentrations for hepatocellular carcinoma treatment

Drug-eluting bead transarterial chemoembolization (DEB-TACE) is the most common treatment for unresectable hepatocellular carcinoma (HCC). However, the effect of drug loading concentration and microsphere size on treatment outcomes remains unclear. This retrospective study compares the outcomes of 87 HCC patients who underwent DEB-TACE with half-loaded or full-loaded doxorubicin (maximum capacity 50 mg/mL) in 75-µm or 100-µm microspheres. Treatment with 100-μm microspheres resulted in significantly lower rates of procedure-related complications (6.6% vs. 26.9%; P < 0.05), post-embolization syndrome (32.8% vs. 61.5%, P < 0.05), SIR complications (32.8% vs. 61.5%; P < 0.01) and adverse events involving abdominal pain (19.7% vs. 42.3%; P < 0.05). Half-load doxorubicin microspheres resulted in greater treatment response (OR, 4.00; 95% CI 1.06–15.13; P, 0.041) and shorter hospital stays (OR, − 1.72; 95% CI − 2.77–0.68; P, 0.001) than did microspheres loaded to full capacity. Stratified analysis further showed that patients treated with 100-μm half-load doxorubicin microspheres had a higher CR (63.6% vs 18.0%) and ORR (90.9 vs 54.0%) and a shorter hospital stay (1.6 ± 1.3 vs 4.2 ± 2.3 days) than did those treated with full-load microspheres (P < 0.05). Thus, the drug-loading concentration of microspheres in DEB-TACE should be carefully considered.

Post-administration dosimetry in yttrium-90 radioembolization through micro-CT imaging of radiopaque microspheres in a porcine renal model

The purpose of this study is to perform post-administration dosimetry in yttrium-90 radioembolization through micro-CT imaging of radiopaque microsphere distributions in a porcine renal model and explore the impact of spatial resolution of an imaging system on the extraction of specific dose metrics. Following the administration of radiopaque microspheres to the kidney of a hybrid farm pig, the kidney was explanted and imaged with micro-CT. To produce an activity distribution, 400 MBq of yttrium-90 activity was distributed throughout segmented voxels of the embolized vasculature based on an established linear relationship between microsphere concentration and CT voxel value. This distribution was down-sampled to coarser isotropic grids ranging in voxel size from 2.5 to 15 mm to emulate nominal resolutions comparable to those found in yttrium-90 PET and Bremsstrahlung SPECT imaging. Dose distributions were calculated through the convolution of activity distributions with dose-voxel kernels generated using the GATE Monte Carlo toolkit. Contours were computed to represent normal tissue and target volumes. Dose-volume histograms, dose metrics, and dose profiles were compared to a ground truth dose distribution computed with GATE. The mean dose to the target for all studied voxel sizes was found to be within 5.7% of the ground truth mean dose. was shown to be strongly correlated with image voxel size of the dose distribution (r 2 = 0.90). is cited in the literature as an important dose metric and its dependence on voxel size suggests higher resolution dose distributions may provide new perspectives on dose-response relationships in yttrium-90 radioembolization. This study demonstrates that dose distributions with large voxels incorrectly homogenize the dose by attributing escalated doses to normal tissues and reduced doses in high-dose target regions. High-resolution micro-CT imaging of radiopaque microsphere distributions can provide increased confidence in characterizing the absorbed dose heterogeneity in yttrium-90 radioembolization.

Hollow Co3O4 nanoparticles immobilized rGO/Carbon monolith as an electrode material for high-performance supercapacitors

In this work, we prepared a hollow Co3O4 nanoparticles (NPs) immobilized reduced graphene oxide (rGO)/carbon monolith (HCGCM) via a one-step carbonization method. The doping of nanomaterial and transition metal oxide can improve the poor conductivity and low capacitance of pure carbonaceous materials. The optimal addition concentration of polystyrene microspheres as a template provided the HCGCM composite with a hierarchical pore structure and a large specific surface area (1600 cm2/g), which is conducive to generating sufficient electroactive sites. At the same time, three dimensional (3D) interconnected pores shorten ion transport paths and reduced diffusion resistance of ions. Due to the existence of pseudocapacitive behavior, the HCGCM composite, as an electrode material working in a three-electrode system, achieved a high capacitance value of 1106 F/g at a current density of 1 A/g. In two-electrode system, the asymmetric supercapacitor had excellent stability performance and remained about 86.7% capacitance after 5000 cycles test. Moreover, it also exhibited a maximum energy density of 66.7 Wh/kg at power density of 750 W/kg. Thus, the strategy of manufacturing 3D porous electrodes is beneficial to improve the overall electrochemical performance of supercapacitors.

Optimization of zero-shear viscosity for HPAM-Polystyrene microspheres formulations through experimental design approach

In this work, the reinforcing effects of polystyrene microspheres in a hydrolyzed polyacrylamide (HPAM) matrix was studied. The experimental design approach was used to optimize the rheological behavior of the HPAM polymer. The effects of three important parameters, including the size of the polystyrene microspheres, their concentration, and the test temperature on the zero-shear viscosity of HPAM polymer solutions were considered. The results showed that the size of the microspheres and test temperature were the most influential factors simultaneously. Moreover, the optimal zero-shear viscosity, at 20 °C, was predicted to be at microspheres concentration of 50 ppm and microspheres size of 1000 nm. The results showed close agreement between the predicted results by the RSM method and those obtained experimentally.

Studies on Preparation, Characterization and Application of Porous Functionalized Glycidyl Methacrylate-Based Microspheres.

A one-step swelling and polymerization technique was used in the synthesis of porous glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA) monodisperse polymeric microspheres. The polystyrene (PS) seed obtained in the dispersion polymerization was used as a shape template. The presence of epoxide rings in the chemical structure of microspheres enables their post-polymerization chemical modifications involving: the Diels-Alder reaction with sodium cyclopentadienide and maleic anhydride, the reaction with 4,4′-(bismaleimido)diphenylmethane, and the thiol-Michael reaction with methacryloyl chloride and 2-mercaptopropionic acid. Changing the reaction mixture composition—the amounts of crosslinking monomer and PS seed as well as the type and concentration of porogen porous microspheres of different porous structures were obtained. Their porous structures were characterized in the dry and swollen states. The copolymers obtained from the equimolar monomers mixture modified in the above way were applied as the column packing materials and tested in the reverse-phase HPLC (High-Performance Liquid Chromatography). A few factors influencing morphology and porous structure of microspheres were studied.

Preparation of bacteriostatic microspheres loading potassium diformate using emulsification/external gelation

Potassium diformate (KDF) is a good substitute for antibiotics in animal feed. Based on the response surface methodology for optimizing the preparation conditions of microspheres. The optimal formulation was as follows: the concentration of ALG was 2 %, the concentration of CaCl2 was 2 %, and 0.4 mL of surfactant. The objective of the present study was to microencapsulate the KDF antibacterial microspheres by emulsification/external gelation. The structure, morphology and thermal properties of the obtained microspheres were characterized by XRD, SEM, FT-IR and TGA. Additionally, the encapsulation efficiency (EE%), loading capacity (LC%), antibacterial and slow-release properties of the prepared microparticles were evaluated. The results show that the optimized microspheres had spherical in morphology, in size, from 2 μm to 10 μm. Finally, the results of the in vitro antibacterial test showed that, when the concentration of antibacterial microspheres was 96 mg/mL, the antibacterial rates against Escherichia coli (E. coli) and Staphylococcus aureus were 89 % and 87 %, respectively, which effectively inhibited the excessive growth of the bacteria. The release kinetics model of the KDF microspheres in vitro revealed that the first-order release mechanism and Hixon-Crowell release mechanism were the primary release mechanisms, and the action time in the intestine could be delayed to 5 h.

An innovative approach to the application of ultrasounds to remove polyethylene microspheres from activated sludge

During the secondary treatment of Wastewater Treatment Plants (WWTP) previous studies have reported that microplastics (MPs), which correspond to plastic fragments smaller than 5 mm, are mostly retained in the activated sludge. Since the sludge can be applied as a fertilizer in agricultural land, the presence of MPs in this matrix can lead to soil contamination. In this study, the application of ultrasounds at a frequency of 80 kHz was tested to remove polyethylene (PE) microspheres from activated sludge samples in order to reduce their concentration in this organic matrix. The application of ultrasounds at a power of 50 W and 8 min 45 sec promoted the removal of 48 ± 4% of MPs from the mixed liquor (2820 ± 51 mg/L of TSS). However, under the same operating conditions, 12 ± 4% of MPs were recovery from the concentrated mixed liquor (9395 ± 164 mg/L of TSS). For the concentrated sludge, a higher power and a longer sonication time (80 kHz; 90 W; 30 min) was necessary to improve the MP recovery. Under these conditions 38 ± 4% of MPs were removed from the sludge. This is the first study applying ultrasounds to remove MPs from activated sludge and the results indicate that ultrasonication can be a suitable instrument in minimizing the concentration of PE microspheres in activated sludge, and thereby minimizing soil contamination when biosolids are applied to agriculture.

Tetrasulfonate calix[4]arene modified large pore mesoporous silica microspheres: Synthesis, characterization, and application in protein separation

Effective protein adsorption by solid matrices from complex biological samples has attracted attention for broad application in biomedical field. Immobilization of calixarenes to solid supports is an essential process for their application in protein separation and purification. Silica is the most widely used support material in calixarene immobilization. With high concentration of polymer microspheres as templates, the large pore mesoporous silica microspheres with controllable, uniform size and structure were successfully synthesized and the resulting large pore mesoporous silica microspheres were modified with water-soluble tetrasulfonate calix[4]arene of unique hollow cavity-shaped structure. The tetrasulfonate calix[4]arene modified large pore mesoporous silica microspheres (SCLX4@LPMS) were characterized by diverse analytical techniques and their protein adsorption performance were also investigated. The obtained SCLX4@LPMS gave rise to an adsorption efficiency of >90% for cytochrome c and lysozyme within a wide pH range of 3.0–10.0 and possessed remarkably high adsorption capacity of cytochrome c (363.64 mg g−1) and lysozyme (166.11 mg g−1). The retained cytochrome c and lysozyme can be readily eluted by using phosphate buffer solution containing NaCl as a stripping reagent with the recoveries of 81% and 86% after 5 times enrichment, respectively. The SCLX4@LPMS microspheres have been applied for the selective adsorption of proteins in real samples and had the application potential in protein adsorption, drug delivery, biosensors, and other biomedical fields.

Rapid self-assembly preparation of p-nitrophenol-molecular imprinted photonic crystal sensors

To overcome the long period of three-dimension photonic crystal colloidal array preparation, a rapid self-assembly method is proposed. The effect of microspheres diameter and concentration, heating and nitrogen blowing have been also studied. According to the results, when the microspheres suspension concentration is 0.2 wt% and heating temperature of 70 °C, a highly regular 3D face-centered cubic colloidal crystal array structure self-assembles on the gas-liquid interface within 3 min. Then using this method, a p-nitrophenol-molecular (p-NP) imprinted photonic crystal sensor with high selectivity and sensitivity is prepared. The p-NP imprinted sensor presents twice signal intense than the non-imprinted sensor towards the target, and the structural color changes from blue to green. Meanwhile, the sensor responds in 3 min and can be reversible more than 9 times. This rapid self-assembly method provides a suitable way for large-area colloidal photonic crystal preparation with higher efficiency and good repeatability, which has a high value for practical applications.

Prepared self-growth supported copper catalyst by recovering Cu (II) from wastewater using geopolymer microspheres

Recycling metals from adsorbents is a promising strategy for utilizing metal resources with better efficiency, and improving environmental protection. In this work, NaOH-activated slag-based geopolymer microspheres (NaOH-SGS) were synthesized by the one-pot suspension solidification method. As regards Cu(II) adsorbents, their maximum adsorption capacity of 335.43 mg/g was much higher than other geopolymer materials. There are obvious changes after Cu2+ adsorption as follows. The average pore diameter of microspheres decreased from 19.91 to 10.80 nm; the pore volume increased from 0.05 to 0.27 cm3/g; the Brunauer−Emmett−Teller (BET) surface area increased from 8.23 to 91.72 m2/g; and the apparent morphology changed from gel-like layer to copper-containing nano-rods. As a result, the number of active sites for the adsorption of Cu2+ ions considerably increased. So self-growth adsorption process was named. Meanwhile the adsorbed Cu2+ species were evenly distributed on the NaOH-SGS surface. The spontaneous endothermic adsorption process which was mainly controlled by the diffusion through the external boundary layer was adequately described by the pseudo-second-order kinetic and Langmuir isotherm models. As to catalyst, the NaOH-SGS after Cu2+ adsorption (NaOH-SGS-Cu) was recycled and calcined (NaOH-SGS-Cu-calcined) to produce a supported copper catalyst that was successfully utilized to remove NO by CO. Although the optimum catalytic temperature for N2 selectivity (SN2 = 78.15%) and NO conversion (XNO = 91.96%) was a little high (350 °C), NaOH-SGS-Cu-calcined exhibits good sulfur resistance as slag contained a certain amount of sulfur. The obtained results indicated that the described method can be effectively used for copper recycling and the copper content of NaOH-SGS-Cu catalyst can be easily adjusted by varying the pH of solution, dosage, contact time, initial microsphere concentration and temperature. NaOH-SGS could be a bifunctional material (Cu2+ adsorbent and catalyst support).

Low-density polydicyclopentadiene through the use of microspheres

The ring opening metathesis polymerization of dicyclopentadiene in the presence of ruthenium-based complexes is a facile way to introduce the fillers into resin bulk. The unexpanded microspheres used as fillers allow decreasing in polymer density. Optimum conditions were found that provide a balance between the expansion rate of microspheres and the curing rate of dicyclopentadiene. In addition, the impact of the type and concentration of microspheres on the density of the obtained polymers and their physical and mechanical properties was studied. The optimal content of microspheres, creating a good balance between lower density and properties, should be considered as 1%, while the optimal concentration to obtain the lowest density is 5%.

Properties of titanium oxide hollow structure layer for photocatalysis prepared by liquid phase deposition

Through liquid phase deposition (LPD) of TiO2 photocatalyst films on an 800 nm polystyrene (PS) microsphere template, this study prepared a porous, LPD-TiO2 hollow layer (HL) with high specific surface area. An aqueous solution of ammonium hexafluorotitanate mixed with boric acid was used to prepare a TiO2 photocatalyst film. The effects of H3BO3 concentration and PS microsphere solid content on the surface morphology, film composition, and photocatalytic property of the films were investigated. The findings revealed that the LPD-TiO2 hollow film prepared using 0.6 M H3BO3 and a substrate containing 0.4 wt% PS microspheres had higher specific surface area and hydrophilicity than a LPD-TiO2 dense layer (DL). Such properties considerably increase the degradation efficiency of a photocatalyst film. After 6 h, the degradation achieved by the LPD-TiO2 hollow layer prepared using a substrate with PS microsphere concentration of 0.4 wt% was 90.7%, whereas that achieved by the dense LPD-TiO2 was only 64.7%. Moreover, the porous, hollow LPD-TiO2 film exhibited excellent photocatalytic performance and may be widely applied to environmental purification in the future.

Study on the association behavior of synthesized hydrophobically associating polymer microspheres

Cross-linked polyacrylamide microspheres are widely used as in-depth flooding agents in petroleum development due to their unique properties of thickening, salt tolerance, shear resistance, etc. However, these materials still encounter major challenges in high-salinity reservoirs. In this work, a kind of hydrophobically associating polymer microspheres called P(AM-S) was synthesized via an inverse suspension polymerization technique with 2-Acrylamidohexadecanesulfonic acid (S) as a hydrophobic monomer. The association behavior and mechanism of P(AM-S) were investigated by hydrodynamic size, morphology, microstructure, fluorescence analyses. The results revealed that the critical association concentration (CAC) of the synthesized P(AM-S) was 5000 mg/L. When the microsphere concentration reached the CAC, the microspheres aggregated to form a sheet-like region. The average particle size and apparent viscosity of the microspheres both decreased first and then increased with increasing NaCl concentration, showing excellent salt tolerance. This type of material is expected to be applied in high-salinity reservoirs.

Design of a Multiplexed Analyte Biosensor using Digital Barcoded Particles and Impedance Spectroscopy

Multiplexing allows quantifying multiple analytes in a single step, providing advantages over individual testing through shorter processing time, lower sample volume, and reduced cost per test. Currently, flow cytometry is the gold standard for biomedical multiplexing, but requires technical training, extensive data processing, and expensive operational and capital costs. To solve this challenge, we designed digital barcoded particles and a microfluidic architecture for multiplexed analyte quantification. In this work, we simulate and model non-fluorescence-based microfluidic impedance detection with a single excitation and detection scheme using barcoded polymer microparticles. Our barcoded particles can be designed with specific coding regions and generate numerous distinct patterns enabling digital barcoding. We found that signals based on adhered microsphere position and relative orientation were evaluated and separated based on their associated electrical signatures and had a 7 µm microsphere limit of detection. Our proposed microfluidic system can enumerate micron-sized spheres in a single assay using barcoded particles of various configurations. As representation of blood cells, the microsphere concentrations may provide useful information on disease onset and progression. Such sensors may be used for diagnostic and management of common critical care diseases like sepsis, acute kidney injury, urinary tract infections, and HIV/AIDS.