Ultra-sensitive detection of brain-derived neurotrophic factor (BDNF) in the brain of freely moving mice using an interdigitated microelectrode (IME) biosensor

Abstract

Brain-derived neurotrophic factor (BDNF) plays a critical role in cognitive processes including learning and memory. However, it has been difficult to detect BDNF in the brains of behaving animals because of its extremely low concentration, i.e., at the sub-nanogram/mL level. Here, we developed an interdigitated microelectrode (IME) biosensor coated with an anti-BDNF an anti-BDNF antibody in a polydimethylsiloxane (PDMS)-based microfluidic channel chip. This sensor could detect BDNF from microliter volumes of liquid samples even at femtogram/mL concentrations with high selectivity over other growth factors. Using this biosensor, we examined whether BDNF is detectable from periodical collection of cerebrospinal fluid microdialysate, sampled every 10 min from the hippocampus of mice during the context-dependent fear-conditioning test. We found that the IME biosensor could detect a significant increase in BDNF levels after the memory task. This increase in BDNF levels was prevented by gene silencing of BDNF, indicating that the IME biosensor reliably detected BDNF in vivo. We propose that the IME biosensor provides a general-purpose probe for ultrasensitive detection of biomolecules with low abundance in the brains of behaving animals.

Combined Dendritic and Axonal Deterioration Are Responsible for Motoneuronopathy in Patient-Derived Neuronal Cell Models of Chorea-Acanthocytosis

“…BDNF levels in the brain are dependent on external stimuli. During context-dependent fear-conditioning tests in mice, the baseline BDNF concentration in the cerebrospinal fluid was estimated at 1-10 pg/mL [28]. Endogenous levels of BDNF in the human brain are not well documented, however, we believe that the herein used concentration is exceeding the average concentration and therefore should result in a constant activation of BDNF receptors.…”

“…We conducted our experiments in a smNPC-derived neuronal cell model system, since they are shown to generate a reproducible amount of midbrain dopaminergic neurons as well as hindbrain specific motoneurons-which is ideal for our investigative scope of not-primarily affected neuronal subtypes in ChAc. We derived smNPC from iPSCs, as reported previously [22,26,28]. In short, we cleaned spontaneous differentiated colonies off adherent iPSC cultures and incubated with 2 mg/mL type IV collagenase for one hour.…”

Dietary fats promote functional and structural changes in the median eminence blood/spinal fluid interface—the protective role for BDNF

“…The slides were incubated overnight at 4 °C with either anti-IGFBP2 (sc-365368, 1:200, Santa Cruz Biotechnology, Dallas, TX, USA), anti-FGF10 (ABN44, 1:200, Merck Millipore, Temecula, CA, USA), anti-vimentin (sc-373717, 1:200, Santa Cruz Biotechnology, Dallas, TX, USA), anti-GFAP (ab7260, 1:1000, ABCAM, Cambridge, UK), anti-BDNF (sc-546, 1:200, Santa Cruz Biotechnology, Dallas, TX, USA), or anti-TrkB (sc-8316, 1:200, Santa Cruz Biotechnology, Dallas, TX, USA) in a blocking solution (1% bovine serum albumin), then for 1 h with goat Anti-Mouse FITC ® (sc-2010, 1:200, Santa Cruz Biotechnology, Dallas, TX, USA) and goat Anti-rabbit Cy3 ® (ab6941, ABCAM, 1:500, ABCAM, Cambridge, UK) in a blocking solution, and the nuclei were stained with (TO-PRO ® -3 Iodide (642/661), T3605, 1:1000, Life Technologies, Carlsbad, CA, EUA) in PBS. The specificity of the antibodies have been tested either by others [ 17 – 20 ] or by us, by performing immunodepletion experiments. Negative controls were performed by omitting the first antibody.…”

Minimally Invasive and Regenerative Therapeutics

“…Biosensors have been utilized to monitor regenerative therapeutics in specific parts of the body [361] . For example, wireless and bioresorbable sensors were developed and implanted into deep areas of the brain [362] (Figure 3C).…”