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Paper-based chips (PB-chips; also referred to as lab-on-paper chips) are using patterned paper as a substrate in a lab-on-a-chip platform. They represent an outstanding technique for fabrication of analytical devices for multiplex analyte assays. Typical features include low-cost, portability, disposability and small sample consumption. This review (with 211 refs.) gives a comprehensive and critical insight into current trends in terms of materials and techniques for use in fabrication, modification and detection. Following an introduction into the principles of PB-chips, we discuss features of using paper in lab-on-a-chip devices and the proper choice of paper. We then discuss the versatile methods known for fabrication of PB-chips (ranging from photolithography, plasma treatment, inkjet etching, plotting, to printing including flexographic printing). The modification of PB-chips with micro- and nano-materials possessing superior optical or electronic properties is then reviewed, and the final section covers detection techniques (such as colorimetry, electrochemistry, electrochemiluminescence and chemiluminescence) along with specific (bio)analytical examples. A conclusion and outlook section discusses the challenges and future prospectives in this field. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Herein, a facile and efficient method was developed for fabrication of solid-state electrochemiluminescence (ECL) sensor via non-covalent π-π stacking and covalent bonding on the graphite electrode (GE) surface. The electrode was firstly modified with 1-aminopyrene via π-π stacking between GE surface and the pyrene moiety. Thereafter a stable and efficient solid-state ECL sensor was fabricated by covalent immobilization of ruthenium(II) onto the GE surface via amidation reaction between the 1-aminopyrene and bis(2,2′-bipyridyl)(4-methyl-4′-carboxypropyl-2,2′-bipyridyl) ruthenium(II) bishexafluorophosphate. The sensor has been investigated using tripropylamine and tetracycline as representative analytes, and low detection limits of 0.7 nM and 3.5 nM (S/N=3) were reached, respectively. [ABSTRACT FROM AUTHOR]

As a representative member of two dimensional MXenes, the OH-terminated Ti 3 C 2 (Ti 3 C 2 T x ) is metallically conducting, with electrical conductivity as high as 6500 S cm −1 . In addition, the terminated groups such as OH make Ti 3 C 2 negatively charged. Based on these superiorities, Ti 3 C 2 T x MXene was herein used to form composite film with Nafion for the solid-state ECL sensor construction for the first attempt. The utilization of Ti 3 C 2 T x not only endow the composite film with much higher conductivity, but also enhance the adsorption amount of Ru(bpy) 3 2+ on the electrode surface. The as-proposed sensor was investigated using tripropylamine as a representative ECL coreactant and low detection limit (S N −1 ≥3) of 5 nM was achieved. It also exhibited much excellent reproducibility (relative standard deviations of (0.69% for 107 continuous cycles) and long-term stability (about 90% of its preliminary ECL intensity can be retained after intermittent use over a 90-day period). In addition, the application potential of the as-prepared sensor was verified by the single-nucleotide mismatch discrimination in human urine. As a result, the as-prepared sensor was proved to be with the superiorities of easy-operation, simplicity, long-term stability, and applicability. [ABSTRACT FROM AUTHOR]