Additive manufacturing, also known as 3D-printing, is receiving great interest by chemists due to the easy design of novel materials, fast prototyping and reducing waste, which enables large-scale fabrication of electrochemical devices. Herein we demonstrate the development of (bio)sensors for the analysis of biological fluids using 3D-printing. Fused deposition modelling was used to fabricate (bio)sensing platforms from commercially-available filaments made of polylactic acid containing graphene (G-PLA). An enzymatic glucose biosensor fabricated on the G-PLA surface was developed and applied for glucose sensing in blood plasma using chronoamperometry. Oxygenated groups from the polymeric matrix provides suitable condition to enzyme immobilization by crosslinking with glutaraldehyde. The biosensor presented a limit of detection (LOD) of 15 μmol L−1, inter-day and intra-day precision lower than 5 %, and adequate recovery values (90–105 %) for the analysis of plasma. We also show that the surface treatment of the 3D-printed sensor (mechanical polishing followed solvent immersion) provides improved electrochemical properties for the direct detection of nitrite and uric acid. Differential-pulse voltammetry and multiple-pulse amperometry under flow conditions were evaluated and compared for the determination of both species in saliva and urine. Highlights are presented for the amperometric detection within a linear range from 0.5–250 μmol L−1 for both analytes, LODs of 0.02 and 0.03 μmol L−1 for uric acid and nitrite, respectively, and high precision (RSD

3D-Printed graphene/polylactic acid electrode for bioanalysis: Biosensing of glucose and simultaneous determination of uric acid and nitrite in biological fluids

Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host–guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.

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Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids

Modern creatinine (Bio)sensing: Challenges of point-of-care platforms.

3D printing has attracted the attention of analytical chemists. 3D printing possesses the merits of fast and low-cost fabrication of geometrically complex 3D structures and has been employed in the fields of microfluidic devices, electrochemical sensors and biosensors, separation sciences, sample pretreatment, and wearable sensors. We focus on the applications and materials of 3D printing in microfluidic devices, separation sciences, and extraction over the last three years and we offer outlook. It is clear that the 3D printing in separation science is here to stay and with new materials development, to develop to on demand fabrication of separation tools.

Recent advances of 3D printing in analytical chemistry: Focus on microfluidic, separation, and extraction devices

Microextraction approaches for bioanalytical applications: An overview.

In this work, inexpensive manufacturing of unibody transparent mesofluidic platforms for pressure-driven Lab-On-a-Valve (LOV) methodologies is accomplished via rapid one-step 3D prototyping from digital models by user-friendly freeware. Multichannel architecture having 800–1800 μm cross-sectional features with unconventional 3D conduit structures and integrating optical and electrochemical detection facilities is for the first time reported. User-defined flow-programming capitalizing upon software control for automatic liquid handling is synergistically combined with additive manufacturing based on stereolithographic 3D printing so as to launch the so-called fourth generation of microflow analysis (3D-μFIA). Using an affordable consumer-grade 3D printer dedicated LOV platforms are 3D printed at will and prints are characterized in terms of solvent compatibility, optical and mechanical properties, and sorption of inorganic and organic species to prospect potentialities for the unfettered choice of chemistr...

3D Printing: The Second Dawn of Lab-On-Valve Fluidic Platforms for Automatic (Bio)Chemical Assays

3D printed flow-through cuvette insert for UV-Vis spectrophotometric and fluorescence measurements.

Optoelectronic detectors for flow analysis systems manufactured by means of rapid prototyping technology.

Three compact flow analysis systems based on flow-through optoelectronic devices and microsolenoid pumps and valves dedicated for determination of urea in effluent liquid produced by artificial kidney in the course of hemodialysis treatments have been developed. The developed photometric devices operate according to paired detector diode principle. For the first flow analysis system an optoelectronic urea biosensor based on pH-sensitive film enzymatically modified with urease has been applied. In the second system open-tubular urease biosensor and optical detector of ammonia by Berthelot reaction have been used. The third non-enzymatic analytical system is based on optoelectronic detector of the product formed in reaction of urea with modified Ehrlich reagent. The analytical utility of developed flow analysis systems has been tested with real samples of spent dialysate. The results of dialysate urea nitrogen determination are comparable with those obtained using reference off-line method recommended for clinical analysis. Advantages and drawbacks of developed prototypes have been compared and discussed.

Michał Michalec

Papers

3D Printing: The Second Dawn of Lab-On-Valve Fluidic Platforms for Automatic (Bio)Chemical Assays

3D printed flow-through cuvette insert for UV-Vis spectrophotometric and fluorescence measurements.

Optoelectronic detectors for flow analysis systems manufactured by means of rapid prototyping technology.

Optoelectronic detectors and flow analysis systems for determination of dialysate urea nitrogen

A multicommutated tester of bioreactors for flow analysis.